Gaussian 03 Manual

5/12/2018

Gaussian 03Manual-slidepdf.com

Gaussian 03 Online Manual Last update: 19 September 2003

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Introduction o About Gaussian 03 o Gaussian 03 Citation o Additional Citation Recommendations Using the G03W Program Running Gaussian 03 o Configuring the Gaussian Environment o Setting Up the Default Route File o Efficient Use of Gaussian o Running Test Jobs o Program Limits Preparing Input Files o About Gaussian Input o Job Types o Model Chemistries o Basis Sets o The Title Section o Molecule Specifications o Multi-Step Jobs Gaussian 03 Keywords Gaussian 03 Utilities

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Additional Information About Z-Matrices References

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Gaussian 03 Online Manual Last update: 4 April 2003

Gaussian 03 Capabilities Gaussian has been designed with the needs of the user in mind. All of the standard input

is free-format and mnemonic. Reasonable defaults for input data have been provided, and the output is intended to be self-explanatory. Mechanisms are available for the sophisticated user to override defaults or interface their own code to the Gaussian system. The authors hope that their efforts will allow users to concentrate their energies on the application of the methods to chemical problems and to the development of new methods, rather than on the mechanics of performing the calculations. The technical capabilities of the Gaussian 03 system are listed in the subsections below. Fundamental Algorithms •

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Calculation of one- and two-electron integrals over any general contracted gaussian functions. The basis functions can either be cartesian gaussians or pure angular momentum functions, and a variety of basis sets are stored in the program and can be requested by name. Integrals may be stored in memory, stored externally, or be recomputed as needed [20,21,22,23,24,25,26,27,28]. The cost of computations can be linearized using fast multipole method (FMM) and sparse matrix techniques for certain kinds of calculations [29,30,31,32,33,34]. Transformation of the atomic orbital (AO) integrals to the molecular orbital basis by "in-core" means (storing the AO integrals in memory), "direct" means (no integral storage required), "semi-direct" someondisk storage of integrals), or "conventional" means (withmeans all AO(using integrals disk). Use of density fitting to speed up the Coulomb part of pure DFT calculations [35,36]. Numerical quadrature to compute DFT XC energies and their derivatives.

Energies •

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Molecular mechanics calculations using the AMBER [37], DREIDING [38] and UFF [39,40] force fields. Semi-empirical calculations using the CNDO [41], INDO [42], MINDO/3 [43,44], MNDO [43,45,46,47,48,49,50,51,52], AM1 [43,48,49,53,54], and PM3 [55,56] model Hamiltonians. Self-consistent field calculations using closed-shell (RHF) [57], unrestricted open-shell (UHF) [58], and restricted open-shell (ROHF) [59] Hartree-Fock wavefunctions. Correlation energy calculations using Møller-Plesset perturbation theory [60] carried to second, third [61], fourth [62,63], or fifth[64] order. MP2 calculations


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use direct [21,65] and semi-direct methods [23] to use efficiently however much (or little) memory and disk are available. Correlation energy calculations using configuration interaction (CI), using either all double excitations (CID) or all single and double excitations (CISD) [66]. Coupled cluster theory with double substitutions (CCD)[67], coupled cluster theory with both single andusing double substitutions [68,69,70,71], Configuration Interaction single and double(CCSD) substitutions (QCISD)Quadratic [72], and Brueckner Doubles Theory (BD) [73,74]. A non-iterative triples contribution may also be computed (as well as quadruples for QCISD and BD). Density functional theory [75,76,77,78,79], including general, user-configurable hybrid methods of Hartree-Fock and DFT. See this page for a complete list of available functionals. Automated, high accuracy energy methods: G1 theory [80,81], G2 theory [82], G2(MP2) [83] theory, G3 theory [84], G3(MP2) [85], and other variants [86]; Complete Basis Set (CBS) [87,88,89,90,91] methods: CBS-4 [91,92], CBS-q [91], CBS-Q [91], CBS-Q//B3 [92,93], and CBS-QCI/APNO [90], as well as general CBS extrapolation; the W1 method of Martin (with slight modifications) [94,95,96]. General MCSCF, including complete active space SCF (CASSCF) [97,98,99,100], and allowing for the optional inclusion of MP2 correlation [101]. Algorithmic improvements [102] allow up to 14 active orbitals in Gaussian 03. The RASSCF variation is also supported [103,104]. The Generalized Valence Bond-Perfect Pairing (GVB-PP) SCF method [105]. Testing the SCF wavefunctions for stability under release of constraints, for both Hartree-Fock and DFT methods [106,107]. Excited state energies using the single-excitation Configuration Interaction (CISingles) method [108], the time-dependent method for HF and DFT [109,110,111], the ZINDO semi-empiricaland method [112,113,114,115,116,117,118,119,120], the Symmetry Adapted Cluster/Configuration Interaction (SAC-CI) method of Nakatsuji and coworkers [121,122,123,124,125,126,127,128,129,130,131,132,133,134,135].

Gradients and Geometry Optimizations •

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Analytic computation of the nuclear coordinate gradient of the RHF [136], UHF, ROHF, GVB-PP, CASSCF [137,138], MP2 [22,23,139,140], MP3, MP4(SDQ) [141,142], CID [143], CISD, CCD, CCSD, QCISD, Density Functional, and excited state CIS energies [108]. All of the post-SCF methods can take advantage of the frozen-core approximation. Automated geometry optimization to either minima or saddle points [136,144,145,146,147,148], using internal or cartesian coordinates or a mixture of coordinates. Optimizations are performed by default using redundant internal coordinates [149], regardless of the input coordinate system used. Automated transition state searching using synchronous transit-guided quasi Newton methods [150]. Reaction path following using the intrinsic reaction coordinate (IRC) [151,152].


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Two- or three-layer ONIOM [153,154,155,156,157,158,159,160,161,162,163] calculations for energies and geometry optimizations. Simultaneous optimization of a transition state and a reaction path [164]. Conical intersection optimization using state-averaged CASSCF [165,166,167]. IRCMax calculation which locates the point of maximum energy for a transition structure a specified reaction path [168,169,170,171,172,173,174,175,176]. Classical along trajectory calculation in which the classical equations of motion are integrated using analytical second derivatives [177,178,179,180] using either: o Born Oppenheimer molecular dynamics (BOMD) [177,178,179,180,181,182] (see [183] for a review) [184,185,186,187,188]. This can be done using any method for which analytic gradients are available, and can optionally make use of Hessian information. o Propagation of the electronic degrees of freedom via the Atom Centered Density Matrix Propagation molecular dynamics model [188,189,190]. This method has similarity and differences to the related Car-Parrinello approach [191]. thethe discussion of the keyword for details. This can be doneSee using AM1, HF, andADMP DFT methods.

Frequencies and Second Derivatives •

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Analytic computation of force constants (nuclear coordinate second derivatives), polarizabilities, hyperpolarizabilities, and dipole derivatives analytically for the RHF, UHF, DFT, RMP2, UMP2, and CASSCF methods [25,139,192,193,194,195,196,197,198,199], and for excited states using CIS. Numerical differentiation of energies or gradients to produce force constants, polarizabilities, and dipole derivatives for the MP3, MP4(SDQ), CID, CISD, CCD, and QCISD methods [143,200,201,202]. Harmonic vibrational analysis and thermochemistry analysis using arbitrary isotopes, temperature, and pressure. Analysis of normal modes in internal coordinates. Determination of IR and Raman intensities for vibrational transitions [193,194,196,200,203]. Pre-resonance Raman intensities are also available. Harmonic vibration-rotation coupling [204,205,206,207]. Anharmonic vibration and vibration-rotation coupling [204,206,207,208,209,210,211,212,213,214]. Anharmonic vibrations are available for the methods for which analytic second derivatives are available.

Molecular Properties •

Evaluation of various one-electron properties using the SCF, DFT, MP2, CI, CCD and QCISD methods, including Mulliken population analysis [215], multipole moments, natural population analysis, electrostatic potentials, and electrostatic potential-derived charges using the Merz-Kollman-Singh [216,217], CHelp [218], or CHelpG [219] schemes.


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Static and frequency-dependent polarizabilities and hyperpolarizabilities for Hartree-Fock and DFT methods [220,221,222,223,224,225]. NMR shielding tensors and molecular susceptibilities using the SCF, DFT and MP2 methods [226,227,228,229,230,231,232,233,234,235]. Susceptibilities can now be computed using GIAOs [236,237]. Spin-spin coupling constants can also be computedcircular [238,239,240,241] at the intensities Hartree-Fock and DFT levels. Vibrational dichroism (VCD) [242]. Propagator methods for electron affinities and ionization potentials [243,244,245,246,247,248,249]. Approximate spin orbit coupling between two spin states can be computed during CASSCF calculations [250,251,252,253,254]. Electronic circular dichroism [255,256,257,258,259] (see [260] for a review). Optical rotations and optical rotary dispersion via GIAOs [261,262,263,264,265,266,267,268,269,270,271]. Hyperfine spectra: g tensors, nuclear electric quadrupole constants, rotational constants, quartic centrifugal distortion terms, electronic spin rotation terms, nuclear spin rotation terms, dipolar hyperfine and Fermi contact terms [272,273,274,275,276,277,278,279]. Input canterms, be prepared for the widely used program of H. M. Pickett [280].

Solvation Models

All of these models employ a self-consistent reaction field (SCRF) methodology for modeling systems in solution. •

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Onsager model (dipole and sphere) [281,282,283,284], including analytic first and second derivatives at the HF and DFT levels, and single-point energies at the MP2, MP3, MP4(SDQ), CI, CCD, and QCISD levels. Polarized Continuum (overlapping spheres) model (PCM) of Tomasi and coworkers [285,286,287,288,289,290,291,292,293,294,295,296,297,298,299,300,301,302,30 3] for analytic HF, DFT, MP2, MP3, MP4(SDQ), QCISD, CCD, CCSD, CID, and CISD energies and HF and DFT gradients and frequencies. o Solvent effects can be computed for excited states [298,299,300]. o Many properties can be computed in the presence of a solvent [304,305,306]. o IPCM (static isodensity surface) model [307] for energies at the HF and DFT levels. o

SCI-PCM (self-consistent model [307] energies and gradients andisodensity numerical surface) frequencies at the HFfor andanalytic DFT levels.


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Technical Support Information Last update: 24 March 2003

The current required citation for Gaussian 03 is the following (presented in two formats for convenient cutting and pasting): Normal Name Order

Gaussian 03, Revision A.1, M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, J. A. Montgomery, Jr., T. Vreven, K. N. Kudin, J. C. Burant, J. M. Millam, S. S. Iyengar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N. Rega, G. A. Petersson, H. Nakatsuji, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J. E. Knox, H. P. Hratchian, J. B. Cross, C. Adamo, J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. W. Ochterski, P. Y. Ayala, K. Morokuma, G. A. Voth, P. Salvador, J. J. Dannenberg, V. G. Zakrzewski, S. Dapprich, A. D. Daniels, M. C. Strain, O. Farkas, D. K. Malick, A. D. Rabuck, K. Raghavachari, J. B. Foresman, J. V. Ortiz, Q. Cui, A. G. Baboul, S. Clifford, J. Cioslowski, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham, C. Y. Peng, A. Nanayakkara, M. Challacombe, P. M. W. Gill, B. Johnson, W. Chen, M. W. Wong, C. Gonzalez, and J. A. Pople, Gaussian, Inc., Pittsburgh PA, 2003 . Last Name First

Gaussian 03, Revision A.1, Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Montgomery, Jr., J. A.; Vreven, T.; Kudin, K. N.; Burant, J. C.; Millam, J. M.; Iyengar, S. S.; Tomasi, J.; Barone, V.; Mennucci, B.; Cossi, M.; Scalmani, G.; Rega, N.; Petersson, G. A.; Nakatsuji, H.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Klene, M.; Li, X.; Knox, J. E.; Hratchian, H. P.; Cross, J. B.; Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Ayala, P. Y.; Morokuma, K.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Zakrzewski, V. G.; Dapprich, S.; Daniels, A. D.; Strain, M. C.; Farkas, O.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman, J. B.; Ortiz, J. V.; Cui, Q.; Baboul, A. G.; Clifford, S.; Cioslowski, J.; Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.; Martin, R. L.; Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.; Challacombe, M.; Gill, P. M. W.; Johnson, B.; Chen, W.; Wong, M. W.; Gonzalez, C.; and Pople, J. A.; Gaussian, Inc., Pittsburgh PA, 2003 Replace “Revision A.1” with the identifier for the revision of the program that you actually use.

A paper describing the scientific capabilities of Gaussian 03 is in preparation. Once it is published, this reference should be cited thereafter. The advances presented for the first time in Gaussian 03 are the work of M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, J. A. Montgomery, Jr., T. Vreven, K. N. Kudin, J. C. Burant, J. M. Millam, S. S. Iyengar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N. Rega, G. A. Petersson, H. Nakatsuji, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J. E. Knox, H. P. Hratchian, J. B. Cross, C. Adamo, J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin,


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R. Cammi, C. Pomelli, J. W. Ochterski, P. Y. Ayala, K. Morokuma, G. A. Voth, P. Salvador, J. J. Dannenberg, V. G. Zakrzewski, A. D. Daniels, O. Farkas, A. D. Rabuck, K. Raghavachari and J. V. Ortiz. Gaussian 03 Online Manual Last update: 19 September 2003

In general, we recommend citing the original references describing the theoretical methods used when reporting results obtained from Gaussian calculations, as well as giving the citation for the program itself. These references are given in the discussions of the relevant keywords. The only exceptions occur with long established methods such as Hartree-Fock theory which have advanced to the state of common practice and are essentially self-citing at this point. In some cases, Gaussian output will display the references relevant to the current calculation type. Gaussian also includes the NBO program as link 607. If this program is used, it should be

cited separately as: NBO Version 3.1, E. D. Glendening, A. E. Reed, J. E. Carpenter, and F. Weinhold. The original literature references for NBO can also be cited [12,13,14,15,16,17,18,19]. Gaussian 03 Online Manual Last update: 4 April 2003

Using the G03W User Interface • • • • • • •

Getting Started Menus and Toolbars Batch Processing of Gaussian Job Files Converting PDB and other Files Customizing the G03W Interface Setting G03W Execution Defaults Utility Programs Included with G03W



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This chapter explains the Windows approach to the Gaussian program, and gets you up and running with a simple example. INPUT MADE EASY step. A file Every complete of instructions by Gaussian is called a jobhave containing one orsetmore jobs steps isprocessed called a job file . Gaussian job files the 3 letter extension of GJF in the Windows environment. Job files that are composed of multiple jobs steps can have individual steps that are dependent on, or make reference to, previous job steps within the file. In addition, job files may have multiple job steps that have nothing to do with the other steps contained therein.

Beyond multiple job step files, G03W can process batches of job files, through the use of a Batch Control & Batch Control File. While job steps may be stored in files, G03W allows simply entering your job step into Job Entry Form). From here you can begin processing the an on screen form (called job step, and/or save whatthe you've typed in to a GJF file.

PROCESSING OF JOB STEPS AT THE PRESS OF A BUTTON.

Once you have a job step in memory, you can begin, pause, resume and/or kill the processing of that step (or group of steps) from buttons on the Toolbar or menu items. You can even use your favorite editor to edit the input and view the output right from inside of G03W. VIEW GAUSSIAN OUTPUT TWO WAYS

When processing jobs, G03W displays the current output in an on screen, scrollable area, while writing the output to a user defined file. Even if you minimize G03W down to an icon, the processing of the job steps is viewable, as the title of the icon continues to update the current status. FILE CONVERSIONS INTEGRATED

Through the use of the NewZMat utility, you can convert to and from numerous chemistry file formats, and automatically load the results into your favorite editor, or into Gaussian itself for processing. CUSTOMIZE GAUSSIAN TO THE WAY YOU WORK

Taking advantage of the full range of possibilities in the environment, G03W lets you setup your preferences about editors, directories, colors, fonts, warnings, questions and messages, and default behavior with normal and batch processing. LIKE DRAG & DROP ?


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G03W if a fully Drag & Drop-aware program. Select a GJF file in the file manager, drag it over the top of a non-processing Gaussian window or icon, and drop the file. Gaussian will load the file, and if you've customized it to do so, begin processing. Select several GJF files and drop them on Gaussian, and Gaussian builds a Batch Control File with your selections and loads it (and possibly starts processing them). Gaussian 03 Online Manual Last update: 2 October 2003

Menus and Toolbars Main Window • • • • •

File Menu Process Menu Utilities Menu View Menu Main Window Toolbar

Job Edit Window • • • • •

File Menu Edit Menu Set-Start Menu Check Route Menu Job Edit Window Toolbar

Additional Jobs Steps Window • • • •

Step Menu View Menu Check Route Menu Job Step Window Toolbar

Main Window: File Menu

The File menu allows you to create and access Gaussian 03W input files and to set program preferences. New: Create new Gaussian 03W input

(residing only in memory until it is explicitly

saved to disk). Open: Open an existing Gaussian 03W input file. The extension of a Gaussian 03W input file is .GJF. The Open menu item may also be used to load an existing batch control file.


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The batch facility is described later in this section. Finally, it may be used to open a PDB file for conversion (this process is discussed later). Modify: Edit the current input,

via the Existing File Job Edit window.

Preferences : Set Gaussian 03W preferences. Preferences are described in a separate

section later in this document.

Exit: Exit from Gaussian 03W. You will be prompted whether to save any unsaved new

or modified input files as well as any unsaved changes to the preferences. Main Window: Process Menu

The Process menu allows you to manipulate executing jobs. All of its items have equivalent icons in the Job Processing window (described later in this section). Begin Processing: Begin executing the currently loaded input. Pause: Immediately suspend the currently executing job. Pause ® Next Link : Suspend execution of the currently executing job after it completes

the current link. (The Gaussian 03 program is divided into a series of modules known as links. Different links perform different parts of the calculation, and the various links execute sequentially, making up the total job.) Resume: Restart execution of a paused job. Kill Job: Immediately abort the currently executing job. If a batch is running, the next

job in the batch (batches are formally defined later in this section) will begin executing (unless the End Batch Run on Error preference is set). End Batch: Stop executing the current batch when the current job finishes. Kill Batch: Immediately abort the currently executing job and terminate batch processing

without running any more jobs.

Main Window: Utilities Menu

The Utilities menu gives you access to the batch and file conversion facilities and other utilities provided with Gaussian 03W. We’ll consider them in detail later in this manual. Edit Batch List: Edit the currently loaded batch control file (extension .BCF), via the

Edit Batch List window (described later). If no batch control file is loaded, then a new batch list is created and any currently loaded input is erased from memory.


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NewZMat: Convert files using the NewZMat utility. After selecting this option, you

designate the file to be converted from the Open File dialog box. The NewZMat File Conversion window then appears (described later in this document). CubeGen: Generate a cube file for use in a visualization program. You will be prompted

for all necessary information. CubMan: Manipulate or transform one or more existing cube files. You will be prompted for all necessary information. FreqChk : Retrieve frequency and thermochemistry data from a checkpoint file. After

selecting this option, you designate the checkpoint file to be used with the Open File dialog box. FormChk : Convert a binary checkpoint file to an formatted (ASCII) version. After

selecting this option, you designate the checkpoint file to be used with the Open File dialog box. UnFchk : Convert a formatted checkpoint file back to its G03W binary format. After selecting this option, you designate the checkpoint file to be used with the Open File dialog box. ChkChk : Display information about the contents of a checkpoint file. After selecting this

option, you designate the checkpoint file to be used with the Open File dialog box. ChkMove: Convert a binary checkpoint file to a form suitable for moving it to another

kind of computer system. After selecting this option, you designate the checkpoint file to be used with the Open File dialog box. C8603: Convert a binary checkpoint file from a previous Gaussian version to the Gaussian 03 format. External PDB Viewer: View the current molecular structure with an external PDB

viewing program. The program to use is specified in the preferences (described later in this document). Main Window: View Menu

The View menu controls the appearance of the window and enables you to invoke an external text editor. The default settings of the various display options may also be controlled via preferences. The editing options also have icon equivalents (described later in this section). Toolbar: Toggles the display of the toolbar portion of the window. When the toolbar is

visible, this item is checked.


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Processing Output: Toggles the display of the Output Display area

of the window.

When the Output Display area is visible, this item is checked. Status Bar: Toggles the display of the status bar portion of the window, which shows a

brief description of the current menu item. When the status bar is visible, this item is checked. Editor: Invoke the external editor (which editor is used is defined in the preferences). Editor -> Output File: Invoke the external editor on the current output file. Note that an

executing job must be paused before invoking an editor on its output file. Main Window: Help Menu

The Help menu follows standard Windows conventions. Contents: Display the table of contents for the

on-line help.

About: Display an informational window about this version and copy of Gaussian 03W,

including the program version and the serial number of this copy:

Start current job. Immediately pause job. Pause after the current link. Resume executing paused job. Terminate the current job. Edit the current Batch Control File (or create new one). End the current batch after the current job completes. Immediate kill current job and batch. Open external editor.


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Edit G03W output file with external editor.

Job Edit Window: File Menu

The File menu allows you to load and save Gaussian 03 input files. Some of its options have equivalent icons (described later in this section). Load: Load an existing input file (extension .GJF), replacing any current input. If the

filename field is filled in, this file will be loaded. If it is blank, then you will be prompted for the file to load. The loaded file replaces any current input (after prompting for needed saves). If you select the Load option without changing the contents of the filename field, then the current input will revert to the last-saved form on disk (provided that you answer No to the save prompt). Save Job: Save the current

input to its original file (you will be prompted for a filename

if it is newly created input). Save Job As: Save the current input to a file that you specify. External Editor: Invoke the external editor on the current input. The external editor is

specified via the preferences. Abandon Data: Exit from this window, discarding all input

and changes.

Exit: Return to the Job Processing window. Current input is retained but is not

automatically saved. Exit & Run: Return to the Job Processing window and begin executing the current input

(not automatically saved to disk). Job Edit Window: Edit Menu

The Edit menu includes the standard Windows Edit menu options: Undo, Cut, Copy, Paste, and Delete. It also has this additional option: Clear Form: Erase all information in all sections of the window. No warning is given

about any unsaved changes. You can create a new input file from this form by selecting Clear Form, entering the desired input, and then saving it. Job Edit Window: Check-Route Option


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This item runs the Check Route utility on the current input (described later in this document). There is an equivalent icon for this option (described later). Job Edit Window: Set-Start Option

This option enables you to set the starting job step for this input file (additional job steps are discussed later in this section). The default is the main (first) step. Select the starting step by double clicking on the desired step. Exit from the window by choosing Close from the window’s System menu (reached via the close bar in its upper left corner). There is an equivalent icon for this option (described later).

Return to main window and start job. Return to main window. Save all current input to disk. Discard all input and return to main window. Run the Check Route utility. Specify the starting job step. Load an input file (replacing current file).

Additional Jobs Steps Window: Step Menu

The Step menu is used to create, remove, and rearrange the order of job steps. Add Step: Create a new job step after the current one. The contents of the % Section,

Title Section, and Charge & Multipl. areas from the main job are automatically copied to the new step. They may be edited as desired as the additional areas are filled in.


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Delete Step: Remove the current step from the job. Reorder: Change the order of the job steps using the Re-Ordering Data window

(described in a separate section later in this document). Load From File: Replace the current step with the job stored in an external file (you will be prompted for the filename). If the file contains more than one job step itself and the current step is the last job step, then all steps from the file will be loaded in their current order. If the file contains multiple job steps and the current step is not the last step in the job, then only the first step from the file will be loaded, as the current step, and an error message will be displayed. Exit: Return to the Job Edit window. There is an equivalent icon for this menu item

(described later in this section).

Additional Jobs Steps Window: View Menu

The Additional Jobs Steps Window menu allows you to move among the additional jobs steps within the current job. Its items also have equivalent icons (described later in this section). Next Step: Move to the next step (higher numbered) in the job. Prev Step: Move to the previous step

in this job.

Choose Step: Move to the job step number that you specify.

Additional Jobs Steps Window: Check-Route Item

This item runs the Check Route facility on the current input step (described in a separate section later in this document).

Go to next job step. Go to previous job step. Move to a specific job step.


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Run the Check Route utility. Return to the Job Edit window. Gaussian 03 Online Manual Last update: 19 September 2003

Batch processing in G03W is implemented through the use of the Batch Control system and BCF files. Multiple GJF files can be processed when in batch mode. This mode is entered automatically whenever a BCF file is loaded, or when batch data is entered directly. You access this feature via the Utilities=>Edit Batch menu item or via the corresponding toolbar icon: . The built-in batch list editing features allow you to add, edit, delete, specify starting entry, and reorder entries in the batch list. You can also save, load and generate BCF files from this same editor. Any and all modifications you have made to the batch control system are saved in memory, and at exit, you are reminded if you have not saved them to a file. Batch processing can be paused, resumed, ended and killed through menu and toolbar process controls. BCF files are also automatically created if a group of files are dropped onto the G03W form or icon from an appropriate file manager. Lastly, you can control certain aspects of batch processing via Process Preferences selections. The Edit Batch Window

Double clicking on a filename in either the input or output list box allows editing of the individual elements in the list. Add Button: Adds an input/output file pair to the list. Delete Button: Removes the currently highlighted input/output file pair. Reorder Button: Allows the user to reorder the data in the list using the Reorder Data

dialog (see below). Set-Start Button: Sets the starting file to process in the batch.


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Reorder Data

This form allows for the reordering of list based data. The top list box contains those items (Batch Filename data or Additional Job Step names) that can be reordered, in their old order. Double-Clicking on an item in the top list box moves it to the bottom list box which holdsit the new Double-Clicking on an itemitinthere the bottom list boxorder. (New ) moves to the toporder. list box ( Old Order) and places in its original Order To move a group of items from one list box to another, hold down the Shift (select a range) or Control (select specific) key while clicking on your choices. Once your choices are highlighted, pressing the appropriate GROUP button will transfer the items. Only when all the items in the Old Order list box are in the New Order list box can you press OK, and implement the new orderin Edit Batch Window: File Menu New: This menu item clears the batch list and prepare memory for a new list typed in. Open: This menu item loads a BCF

file.

Save: This menu item saves changes to

the already loaded file.

Save As: This menu item saves the contents

of the list to a new filename.

Exit: This menu item exits the Edit Batch area. If there are any entries in the list, G94W

stays in batch processing mode. If not, standard job processing mode is set. Gaussian 03 Online Manual Last update: 19 September 2003

Use this command to translate from one chemistry file format to another, and load a converted file into memory or an external editor. After selecting an appropriate file, the dialog box appears for conversion. Preliminary conversion parameters are preset depending on the file extension of the filename selected. Use the FIND FILE button to quickly select a different conversion source file. Generate File Filename: The system attempts to build an appropriate filename for the

selected source file. The generated file will be created in the same directory as the source file. The file extension will be adjusted as the user selects conversion parameters under output options.


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Load Converted File as Job: Tells the system to load the newly generated file into

memory for further processing by Gaussian. This will only happen if the file conversion was successful. Edit Generated File: Tells the system to load the newly generated

file into memory, and

display it for editing. Ext.Editor->Generated File: Tells the system to load the newly generated file into the

user defined external editor for modification and display. The file is not loaded into Gaussian memory. Input Options: This button allows user control over the NewZMat Input Parameters. Output Options: This button allows user control over the NewZMat Output Parameters. Other Options: This button allows user control over the NewZMat Other Parameters. For more information about NewZMat, consult the Gaussian 03 User's Reference.

Gaussian 03 Online Manual Last update: 2 October 2003

Customizing the G03W Interface G03W allows you to configure to your tastes many aspects of the user interface, including visual aspects and operating procedures. VISUAL PREFERENCES: You can choose actively to display or not to display the toolbar, Processing Output Area and Status Bar via the View Menu on the main form.

These menu items will change the size and shape of the main form, and you can make these choices permanent via the Display Preferences section of the Preferences form. On the display preferences form you can choose to see an hourglass when the a link has control of the CPU, whether or not to have a Motif-like look to Gaussian (raised or lowered 3D controls, gray background), how often to look into the run-time output file and display any new contents, the foreground and background colors to use for the output display area, and the fonts to use for both input and output. You cantochoose how you want be prompted over-writing existing files, and how save complicated jobsto(jobs which areconcerning a conglomeration of multiple files) from the Edit Preferences section of the Preferences form. In addition, each time you run, you may or may not want to be prompted for the name of the output file. The control for this is found under the Process Preferences section. FILES AND MESSAGES:


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CONTROL OVER EVENTS: You can define what happens when a file is loaded (i.e.

do you jump into the internal editor or not), what happens when a file or set of files is dropped on G03W, and how to handle messages, output and errors during batch processing. All these options are controlled from the Process Preferences section. DEFAULT LOGIC: You can also deal with multiple operating paths by setting the default path information on the main Preferences dialog. The BIN PATH entry tells

Gaussian where to find its links. The scratch path entry tells the system where you want

temporary files to be created and re-created. The optional output path tells the system where the default should be to create output files. If left blank, the default for GJF files is the directory where the input file was found, for BCF files, the output filename defines where it goes. The input path tells the system where it should look first to find files. If left blank, the system looks in the directory where you last loaded a file from (in the current session).

ASCII Editor

Fill in this edit area with the fully qualified path and filename of the text editor you prefer to you use. This editor will be available from the edit form menus and the View menu, or from the toolbar button. In addition, after a job has successfully run, the editor can be called from the View menu with the output file, or from the toolbar button. During the initial installation, the ASCII Editor is preset to NOTEPAD.EXE if no other editor has been defined. Find File:

Use this button to quickly locate your preferred editor executable. This function will fill in the edit area with your selection. Bin Path: This edit area tells G03W where

the link executables exist on your system. This information is filled in by the initial installation program and should normally not be altered. WARNING : Having incorrect information will cause all jobs to fail at the first link. Scratch Path: This edit area tells G03W where

the scratch files should be created. If this

edit is empty, the system will assume no scratch directory is present, and all temporary files will be created in the same directory as the input file (if there is one) or the current working directory (if there is no input file). It is highly recommended that you have a scratch directory, as this will reduce the impact of multiple Gaussian job runs, (which can take up lots of disk space), by overwriting the same files.


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Output Path: This edit area tells Gaussian where you would like all output files to be

created. If this is edit is empty, then the output file will be created either where you specify it, or in the same directory that the input file was found in. Input Path: This edit area tells Gaussian you have a preferred default input path to

search GJF files. is empty, then the where currentthe working is used until a file isfor loaded. AfterIfa this file edit is loade, the directory loaded directory file was found, becomes the default. Display: The display button allows control over

the visual elements of the interface. (See

Display Preferences ). Edit: The edit button allows control over the file editing elements of the interface. (See

Edit Preferences ). Process: The process button allows control over the Gaussian Job Step processing

elements of the interface. (See Process Preferences ).

Use this command to adjust the visual elements of the G03W interface to your tastes: Cursor Indication of Processing: This switch toggles whether or not the cursor should

be changed to an hourglass while a link has the CPU. (An indicator of both processing and multitasking). (Default OFF). Motif Look : Toggle whether to use a gray background and add height or depth to on

screen controls. (Default ON). Show ToolBar at Startup: Toggle whether or not to view the toolbar when the program

first opens. (Default ON). Show Output File Area at Startup: Toggle whether or not to view the output of jobs

run when the program first opens. (Default ON). Show Status Bar at Startup: Toggle whether or not to view the Status Bar at the bottom

of the window when the program first opens. (Default ON). Output File Scan Time: Set the time (in seconds) that the front-end should wait to scan

the output file for new information, and display it in the output display area. Range 23600 seconds. (Default: 15secs). Use System Colors: Toggle whether or not to use the colors defined in the current

Windows system color scheme, for aspects of screen display (edits, list boxes, text,


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scrollbars,etc...) Note: Motif Look overrides the color control for window backgrounds, whether or not this toggle button is checked. (Default OFF). Output Background: This button displays the color selection screen to allow the user to

set a color for the background of the output display area. Keep in mind that a color should Output Font below) that will allow seeing the text. also be selected for the text (seeG:0). (Default - Dark Blue R:0 B:64 Output Font: This button displays the font selection box for

the output display area. Since the information in the output assumes a fixed font (terminal like) display, only fixed width fonts are available in this area. In addition, you may select a text color if the Use System Colors switch (above) is off. Note: to see an example in the Sample window, you must fully select a font, (meaning Name, style and size) and the text color must be anything but white. Input Font: This button displays the font selection box for

the input displays (any edit

area area. on the input forms). Any normal font can be used. Colors may not be set for this text edit

Use this command to adjust the file I/O elements of the G03W interface to your tastes: File OverWrite Warnings: Select whether you want notification that you are about to

write over an existing file. • •

•

The first option provides notification anytime this would occur. The second option provides notification only when a file in memory is being saved to a different filename, and that new filename already exists. The last option never bothers the user with notification, and over-writes any previous files (dangerous).

Multi-Step Job File Saves: When the contents of memory comprises multi-step jobs,

whether the user loaded steps from multiple files or not, the steps may be saved in one of three combinations: • • •

Save the steps back to their original files (DEFAULT). Save all the steps to a single file. Save each step to an individual file (filename is created with the step number). The first toggle button controls whether the interface queries the user for a choice when this condition exists.


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Use this command to adjust the job processing elements of the G03W interface to your tastes: Query Output Name: Toggles whether or not to ask the user the name and directory of

the output file to create. (Default ON). Show File On Load: Toggles whether or not

to display the contents of a file after its

loaded. (Default ON). End Batch Run on Error: Toggles whether to halt batch processing when an error occurs, or to skip to the next job in the batch and keep going. (Default ON). Note: If this

feature is active and an error occurs while processing a batch, the batch start entry value is set to the file that caused the error . Scan Output During Batch: Toggles whether or not to display the output of the

currently processing job in the output display area when processing batches of jobs. (Default ON). Minimize Until End / Error: Toggles whether Gaussian should become an ICON while processing batch jobs. If an error occurs or the end of the batch is reached, and this feature is active, then Gaussian will re-display itself in an open state. (Default OFF). Prompt Messages: Toggles whether or not ask questions of the user when processing

batches, or to assume default behavior. Such questions include file overwrite warnings and non-fatal system errors. (Default OFF). Run Dropped Files: Toggles whether or not to immediately run a file or list of files

dropped on Gaussian by a file manager. (See Drag & Drop in your Windows manual). (Default OFF). Gaussian 03 Online Manual Last update: 6 October 2003

Depending on the characteristics of a particular computer system, it is sometimes necessary for performance reasons to override some of the defaults built into the program. This can be done by creating a site customization file. On Unix systems, this file is named Default.Route, residing in $g03root/g03. Under Windows, the Gaussian defaults file is Default.Rou, and it is located in the Gaussian 03W scratch subdirectory (e.g., C:\G03W\scratch). The format of the file is the same on all computer systems.


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The following subsections describe the types of information which can be supplied in the defaults file. Route Defaults -#- and have the same form as normal route section These parameters are introduced commands. For example, this linebywill set the default SCF algorithm to the conventional (non-direct) algorithm: -#- SCF=Conventional

There may be more than one -#- line in the file. Commands listed in Default.Route change only the defaults; they are overridden by anything specified in the route section of an input file. Thus, if the Default.Route contains: -#- MP2=NoDirect

and the route section contains the MP2 keyword, then the conventional MP2 algorithm will be used. However, if the route section contains the MP2=Direct keyword, then the direct algorithm will be used. All sites will want to specify the amount of scratch disk space available via the MaxDisk keyword in the Default.Route file. For example, the following line sets MaxDisk to 800 MB: -#- MaxDisk=800MB

This line will have the effect of limiting disk usage in the semi-direct algorithms to the specified amount. Some suitable limit should be defined for your configuration. Keep in mind that the more disk space is available, the faster the evaluation, especially for MP2. Default.Route Limitations

Not all route section keywords are honored in the Default.Route file. In general, the rule is that only options which do not affect the outcome of a calculation (i.e., do not change the values of any predicted quantities) are allowed in the file. Thus, SCF=Conven, which changes only the integral storage algorithm, will be honored, while Int(Grid=3), which affects the results of many kinds of calculations, will be ignored. Memory Defaults

It is often the case that Gaussian jobs which unwisely use excessive memory can cause severe difficulties on the system. The -M- directive enforces a default dynamic memory limit. For example, the following line sets default memory use to 32 MB:


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-M- 4000000

Note that this limit can be bypassed with the %Mem Link 0 command. The value may also be followed by KB, MB, GB, KW, MW or GW to indicate units other than words. The default memory size is 6 MW. Number of Processors

If your computer system has multiple processors, and parallel processing is supported in your version of Gaussian, you may specify the default number of processors to use in the Default.Route file. For example, the following command sets the default number of processors to 4: -P- 4

Normally, the program defaults to execution on only a single processor. The %NProcShared Link 0 command can be used to override the default for a specific job. Clearly, the number of processors requested should not exceed the number of processors available, or a substantial decrease in performance will result. Site Name

The site name may be specified by the directive, which sets -S- as the site name to be used in archive entries generated by Gaussian. The default site name is GINC. For example, the following line sets the site name to EXPCONS: -S- EXPCONS

Typical Default Settings

Here are reasonable default settings for various machine configurations: •

For a small workstation with 64 MB memory and 1 GB of disk, the default algorithms and memory allocation are fine. MaxDisk is all that need be specified. -#- MaxDisk=400MB

•

On a powerful workstation with 8 processors and 1 GB of memory, being used for large jobs, all 8 processors should be used by default. Also, more memory should be given to each job: -M- 64MW -P- 8 -#- MaxDisk=10GB

User Defaults Files


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Gaussian users may set their own defaults by creating their own Default.Route file. Gaussian checks the current working directory for a file of this name when a job is

initiated. Settings in the local file take precedence over those in the site-wide file, and options specified in the route section of the job take precedence over both of them. Gaussian 03 Online Manual Last update: 4 April 2003

Utility Programs This page discusses various utility programs included with Gaussian 03. The utilities are discussed in alphabetical order within this chapter. Most utilities are available for both UNIX and Windows versions of Gaussian. However, be sure to consult the release notes accompanying the program for information pertaining to specific operating systems. The following lists the available utilities and their functions (starred items are included on the Gaussian 03W Utilities menu): Converts checkpoint files from previous program versions to Gaussian 03 format. chkchk * Displays the route and title sections from a checkpoint file. cubegen* Standalone cube generation utility. Manipulates Gaussian-produced cubes of electron density and electrostatic cubman* potential (allowing them to be added, subtracted, and so on). Converts a binary checkpoint file into an ASCII form suitable for use with formchk * visualization programs and for moving checkpoint files between different types of computer systems. Prints frequency and thermochemistry data from a checkpoint file. Alternate freqchk * isotopes, temperature, pressure and scale factor can be specified for the thermochemistry analysis. freqmem Determines memory requirements for frequency calculations. gauopt Performs optimizations of variables other than molecular coordinates. On-line help for Gaussian. ghelp Standalone molecular mechanics program. mm newzmat* Conversion between a variety of molecular geometry specification formats. Route section syntax checker and non-standard route generation. testrt* Convert a formatted checkpoint file back to its binary form (e.g., after moving unfchk * it from a different type of computer system). c8603


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GAUSS_MEMDEF Environment Variable GAUSS_MEMDEF The environment be used to increase the memory available to utilities which do not offervariable such anmay option themselves. Its value should be set to the desired amount of memory in words. Gaussian 03 Online Manual Last update: 10 October 2003

Running Gaussian This page describes the operating system commands required to execute Gaussian on Unix-based computer systems.for Seeother the additional instructions the program for the equivalent information operating systems. Thisaccompanying discussion assumes that the program has already been installed. The final section lists the component links of the Gaussian 03 program. Running Gaussian involves the following activities: • • • •

Creating Gaussian input describing the desired calculation. Specifying the locations of the various scratch files. Specifying resource requirements. Initiating program execution, in either interactive or batch mode.

In this page, we will assume that a basic Gaussian input file has been created, and our discussion will examine the remaining three items on the list.

Gaussian uses several scratch files in the course of its computation. They include: • • • •

The Checkpoint file: name.chk The Read-Write file: name.rwf The Two-Electron Integral file: name.int The Two-Electron Integral Derivative file: name.d2e

By default, these files are given a name generated from the process ID of the Gaussian process, and they are stored in the scratch directory, designated by the GAUSS_SCRDIR environment variable (UNIX). You may also see files of the form name.inp in this directory. These are the internal input files used by the program. If the environment variable is unset, the location defaults to the current working directory of the Gaussian process.


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By default, these files are deleted at the end of a successful run. However, you may wish to save the checkpoint file for later use in another Gaussian job, for use by a visualization program, to restart a failed job, and so on. This may be accomplished by naming the checkpoint file, providing an explicit name and/or location for it, via a %Chk command within the Gaussian input file. Here is an example: %Chk=water

This command, which is placed at the beginning of the input file (before the route section-see chapter 3 for details), gives the checkpoint file the name water.chk , overriding the usual generated name and causing the file to be saved at job conclusion. In this case, the file will reside in the current directory. However, a command like this one will specify an alternate directory location as well as filename: %Chk=/chem/scratch2/water

If disk space in the scratch directory is limited, but space is available elsewhere on the system, you may want to split the scratch files among several disk locations. The following commands allow you to specify the names and locations of the other scratch files: %RWF= path %Int= path %D2E= path

Read-Write file Integral file Integral Derivative file

In general, the read-write file is by far the largest, and so it is the one for which an alternate location is most often specified. Splitting Scratch Files Across Disks

An alternate syntax is provided for splitting the Read-Write file, the Integral file, and/or the Integral Derivative file among two or more disks (or file systems). Here is the syntax for the %RWF command: %RWF=loc1, size1,loc2, size2, ...

where each loc is a directory location or a file pathname, and each size is the maximum size for the file segment at that location. Gaussian will automatically generate unique filenames for any loc which specifies a directory only. On UNIX systems, directory specifications (without filenames) must include a terminal slash. By default, the sizes are in units of words; the value may be followed by KB, MB or GB (without intervening spaces) to designate KB, MB or GB, respectively, or by KW, MW or GW to indicate units of kilowords, megawords or gigawords, respectively. Note that 1 MB = 10242 bytes = 1,048,576 bytes (not 1,000,000 bytes).


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A value of -1 for any size parameter indicates that any and all available space may be used, and a value of 0 says to use the current size of an existing segment. -1 is useful only for the last file specified, for which it is the default. For example, the following directive splits the Read-Write file across three disks: %RWF=/dalton/s0/,60MW,/scratch/,800MB,/temp/s0/my_job,-1

The maximum sizes for the file segments are 480 MB, 800 MB, and unlimited, respectively. Gaussian will generate names for the first two segments, and the third will be given the name my_job. Note that the directory specifications include terminal slashes. Due to limitations in current UNIX implementations, -1 should be used with caution, as it will attempt to extend a file segment beyond all remaining disk capacity on these systems; using it will also have the side effect of keeping any additional file segments included in the list from ever being used. Saving and Deleting Scratch Files

By default, unnamed scratch files are deleted at the end of the Gaussian run, and named files are saved. The %NoSave command may be used to change this default behavior. When this directive is included in an input file, named scratch files whose directives appear in the input file before %NoSave will be deleted at the end of a run (as well as all unnamed scratch files). However, if the % directive naming the file appears after the %NoSave directive, the file will be retained. For example, these commands specify a name for the checkpoint file, and an alternate name and directory location for the readwrite file, job: and cause only the checkpoint file to be saved at the conclusion of the Gaussian %RWF=/chem/scratch2/water %NoSave %Chk=water

Files to be deleted go here. Files to be saved go here.

Initialization Files

The Gaussian system includes initialization files to set up the user environment for running the program. These files are: $g03root/g03/bsd/g03.login $g03root/g03/bsd/g03.profile

C shell Bourne shell

Note that the g03root environment variable must be set up by the user. Thus, it is customary to include lines like the following within the .login or .profile file for Gaussian users: .login files:


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setenv g03root location source $g03root/g03/bsd/g03.login .profile files: g03root=location export g03root

. $g03root/g03/bsd/g03.profile

Once things are set up correctly, the g03 command is used to execute Gaussian 03 (see below).

The %Mem command controls the amount of dynamic memory to be used by Gaussian. By default, 6 megawords are used. This can be changed to n double-precision words by specifying: %Mem=n

For example, the following command sets memory use to 64 million bytes: %Mem=8000000

The value given to %Mem may also be followed by KB, KW, MB, MW, GB or GW (no intervening spaces) to denote other units. For example, the following command also sets the amount of dynamic memory to 64 MB: %Mem=64MB

Even larger allocations may be needed for very large direct SCF calculations-at least 3 N 2 words, where N is the number of basis functions. Frequency and post-SCF calculations involving f functions should be given 6 MWords if possible. Using more than 6 million words for moderate-sized calculations (i.e., a direct SCF with less than 500 basis functions) does not improve performance on most systems. Warning: Requesting more memory than the amount of physical memory actually available on a computer system will lead to very poor performance.

If Gaussian is being used on a machine with limited physical memory, so that the default of 48 MB is not available, the default algorithms as wellpage as the memory should be set appropriately during installation. See this fordefault more details onallocation using Gaussian efficiently.

Once all input and resource specifications are prepared, you are ready to run the program. Gaussian 03 may be run interactively using one of two command styles:


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g03 job-name g03 output-file

In the first form, the program reads input from job-name.com and writes its output to jobname.log. When job-name is not specified, the program reads from standard input and writes to standard output, and these can be redirected or piped in the usual UNIX fashion. Either form of command can be forced in the background in the same manner as any shell command using &. Scripts and Gaussian

Scripts designed to run Gaussian 03 may also be created in several ways (we will use the C shell in these examples). First, g03 commands like those above may be included in a shell script. Secondly, actual Gaussian input may be included in the script using the << construct: #!/bin/csh g03 <water.log %Chk=water #RHF/6-31G(d) water energy 0 O H H

1 1 1

1.0 1.0

2

120.0

END echo "Job done. "

All lines preceding the string following the << symbols are taken as input to the g03 command. Finally, loops may be created to run several Gaussian jobs in succession. For example, the following script runs all of the Gaussian input files specified as its command line arguments, and it maintains a log of its activities in the file Status: #!/bin/csh echo "Current Job Status:" > Status foreach file ($argv) echo "Starting file $file at `date`" >> Status g03 < $file > $file:r.log echo "$file Done with status $status" >> Status end echo "All Done." >> Status

The following more complex script creates Gaussian input files on-the-fly from the partial input in the files given as the script's command line arguments. The latter are lacking full route sections; their route sections consist of simply a # sign or a # line


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containing special keywords needed for that molecular system, but no method, basis set, or calculation type. The script creates a two-step job for each partial input file-a Hartree-Fock optimization followed by an MP2 single point energy calculation-consisting of both the literal commands included in theby script and thethe contents of each fileinclude specified script execution time. It includes the latter exploiting Gaussian 03 @ file at mechanism: #!/bin/csh echo "Current Job Status:" > Status foreach file ($argv) echo "Starting file $file at `date`" >> Status g03 < $file:r.log %Chk=$file:r # HF/6-31G(d) FOpt @$file/N --Link1-%Chk=$file:r %NoSave # MP2/6-31+G(d,p) SP Guess=Read Geom=AllCheck END echo "$file Done with status $status" >> Status end # end of foreach echo "All Done." >> Status

Batch Execution with NQS

Gaussian may be run using the NQS batch facility on those UNIX systems that support it.

The subg03 command, defined in the initialization files, submits an input file to a batch queue. It has the following syntax: subg03 queue-name job-name [-scrdir dir1] [-exedir dir2] [-p n]

The two required parameters are the queue and job names. Input is taken from jobname.com and output goes to job-name.log , just as for interactive runs. The NQS log file is sent to job-name.batch-log . The optional parameters -scrdir and -exedir are used to override the default scratch and executable directories, respectively. Any other parameters are taken to be NQS options. In particular, -p n can be used to set the priority within the queue to n. This is priority for initiation (1 being lowest), and does not affect the run-time priority. To submit an NQS job from an interactive session, a file like the following should be created (with filename name.job): # QSUB -r name -o name.out -eo # QSUB -lt 2000 -lT 2100 # QSUB -lm 7mw -lM 7mw g03

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where name should be replaced with a name that is appropriate to your calculation. The first line names the running job, names the output file, and causes errors to be included in the output file. The time parameters are different to allow addition of job control for cleanup, (for example, archiving the checkpoint file in the event that the job exceeds its time limit). The memory parameters are used both for initial scheduling of your job for execution and by the program to determine dynamic memory use. This job would then be submitted by issuing the command, $ qsub name.job

and the output would be placed in your current working directory.

The following table lists the component programs of Gaussian 03 —known as links — along with their primary functions: L0 L1 L101 L102 L103 L105 L106 L107 L108 L109 L110 L111 L113 L114 L115 L116 L117 L118 L120 L121 L122

Initializes program and controls overlaying Processes route section, builds list of links to execute, and initializes scratch files Reads title and molecule specification FP optimization Berny optimizations to minima and TS, STQN transition state searches MS optimization Numerical differentiation of forces/dipoles to obtain polarizability/ hyperpolarizability Linear-synchronous-transit (LST) transition state search Potential energy surface scan Newton-Raphson optimization Double numerical differentiation of energies to produce frequencies Double num. diff. of energies to compute polarizabilities & hyperpolarizabilities EF optimization using analytic gradients EF numerical optimization (using only energies) Follows reaction path using the intrinsic reaction coordinate (IRC) Numerical self-consistent reaction field (SCRF) Post-SCF SCRF Trajectory calculations Controls ONIOM calculations ADMP calculations Counterpoise calculations


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L202 L301 L302 L303 L308 L310 L311 L314 L316 L319 L401 L402 L405 L502 L503 L506 L508 L510 L601 L602 L604 L607 L608 L609 L701 L702 L703 L716 L801 L802 L804 L811 L901 L902

Reorients coordinates, calculates symmetry, and checks variables Generates basis set information Calculates overlap, kinetic, and potential integrals Calculates multipole integrals Computes dipole velocity and Rx ∇ integrals Computes spdf 2-electron integrals in a primitive fashion Computes sp 2-electron integrals Computes spdf 2-electron integrals Prints 2-electron integrals Computes 1-electron integrals for approximate spin orbital coupling Forms the initial MO guess Performs semi-empirical and molecular mechanics calculations Initializes an MCSCF calculation Iteratively solves the SCF equations (conven. UHF & ROHF, all direct methods, SCRF) Iteratively solves the SCF equations using direct minimization Performs an ROHF or GVB-PP calculation Quadratically convergent SCF program MC-SCF Population and related analyses (including multipole moments) 1-electron properties (potential, field, and field gradient) Evaluates MOs or density over a grid of points Performs NBO analyses Non-iterative DFT energies Atoms in Molecules properties 1-electron integral first or second derivatives 2-electron integral first or second derivatives (sp) 2-electron integral first or second derivatives (spdf) Processes information for optimizations and frequencies Initializes transformation of 2-electron integrals Performs integral transformation ( N 3 in-core) Integral transformation Transforms integral derivatives & computes their contributions to MP2 2nd derivatives Anti-symmetrizes 2-electron integrals Determines the stability of the Hartree-Fock wavefunction


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L903 L905 L906 L908

Old in-core MP2 Complex MP2 Semi-direct MP2 OVGF (closed shell)

OVGF (open shell) Calculates post-SCF energies and gradient terms L914 CI-Singles, RPA and Zindo excited states; SCF stability L915 Computes fifth order quantities (for MP5, QCISD(TQ) and BD(TQ)) L916 Old MP4 and CCSD L918 Reoptimizes the wavefunction Iteratively solves the CPHF equations; computes various properties (including L1002 NMR) L1003 Iteratively solves the CP-MCSCF equations L1014 Computes analytic CI-Singles second derivatives L1101 Computes 1-electron integral derivatives L1102 Computes dipole derivative integrals L1110 2-electron integral derivative contribution to Fx L1111 2 PDM and post-SCF derivatives L1112 MP2 second derivatives L9999 Finalizes calculation and output L909 L913


Gaussian locates executables and creates scratch files in directories specified by several

environment variables . However, the user is responsible for creating two of them: •

•

g03root : Indicates the directory where the g03 directory resides (i.e., the

directory above it). GAUSS_SCRDIR : Indicates the directory which should be used for scratch files.

The Gaussian initialization files are responsible for initializing other aliases and environment variables as needed. All Gaussian users need to execute the appropriate Gaussian initialization file within their UNIX shell-specific initialization file. See this page for more details. The environment variables created by g03.login and g03.profile include:


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•

•

•

GAUSS_EXEDIR : Specifies the directories in which the Gaussian images are stored. By default it includes the main directory $g03root/g03 and several

alternate directories. GAUSS_ARCHDIR : Specifies the directory in which the main site-wide archive file is kept, and into which temporary archive files should be placed if the main archive is unavailable. It defaults to $g03root/g03/arch if unset. G03BASIS which contains files specifying the standard Gaussian : The directory internally stored basis sets, as well as some additional basis sets in the form of general basis set input. This environment variable is provided for convenience and is designed for use with the @ include mechanism.

Scratch File Considerations

On UNIX systems, Gaussian generates unique scratch file names based on the process ID when no name has been specified by the user. This mechanism is designed to allow multiple Gaussian jobs to execute simultaneously using a common scratch directory. Scratch files are deleted automatically when a job completes successfully or dies cleanly by default. However, scratch files are not deleted when a job is killed externally or otherwise terminates abnormally. Consequently, leftover files may accumulate in the scratch directory. An easy method for avoiding excessive clutter is to have all users share a common scratch directory, and to have that scratch directory cleared at system boot time by adding an rm command to the appropriate system boot script (e.g., /etc/rc or one of the files under /etc/rc.d/rc3.d ). If the NQS batch system is in use, clearing the scratch directory should also be done before NQS is started, ensuring that no jobs are using the directory when it is cleared. Gaussian 03 Online Manual Last update: 6 October 2003

Depending on the characteristics of a particular computer system, it is sometimes necessary for performance reasons to override some of the defaults built into the program. This can be done by creating a site customization file. On Unix systems, this file is named Default.Route, residing in $g03root/g03. Under Windows, the Gaussian defaults file is Default.Rou, and it is located in the Gaussian 03W scratch subdirectory (e.g., C:\G03W\scratch). The format of the file is the same on all computer systems. The following subsections describe the types of information which can be supplied in the defaults file. Route Defaults


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These parameters are introduced by -#- and have the same form as normal route section commands. For example, this line will set the default SCF algorithm to the conventional (non-direct) algorithm: -#- SCF=Conventional

There may be more than one -#- line in the file. Commands listed in Default.Route change only the defaults; they are overridden by anything specified in the route section of an input file. Thus, if the Default.Route contains: -#- MP2=NoDirect

and the route section contains the MP2 keyword, then the conventional MP2 algorithm will be used. However, if the route section contains the MP2=Direct keyword, then the direct algorithm will be used. All sites will want to specify the amount of scratch disk space available via the MaxDisk keyword in the Default.Route file. For example, the following line sets MaxDisk to 800 MB: -#- MaxDisk=800MB

This line will have the effect of limiting disk usage in the semi-direct algorithms to the specified amount. Some suitable limit should be defined for your configuration. Keep in mind that the more disk space is available, the faster the evaluation, especially for MP2. Default.Route Limitations

Not all route section keywords are honored in the Default.Route file. In general, the rule is that only options which do not affect the outcome of a calculation (i.e., do not change the values of any predicted quantities) are allowed in the file. Thus, SCF=Conven, which changes only the integral storage algorithm, will be honored, while Int(Grid=3), which affects the results of many kinds of calculations, will be ignored. Memory Defaults

It is often the case that Gaussian jobs which unwisely use excessive memory can cause severe difficulties on the system. The -M- directive enforces a default dynamic memory limit. For example, the following line sets default memory use to 32 MB: -M- 4000000

Note that this limit can be bypassed with the %Mem Link 0 command. The value may also be followed by KB, MB, GB, KW, MW or GW to indicate units other than words. The default memory size is 6 MW.


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Number of Processors

If your computer system has multiple processors, and parallel processing is supported in your version of Gaussian, you may specify the default number of processors to use in the Default.Route file. For example, the following command sets the default number of processors to 4: -P- 4

Normally, the program defaults to execution on only a single processor. The %NProcShared Link 0 command can be used to override the default for a specific job. Clearly, the number of processors requested should not exceed the number of processors available, or a substantial decrease in performance will result. Site Name

The name may be specified directive, which setssite -S- name as theissite nameFor to be usedsite in archive entries generatedbybythe . The default GINC. Gaussian example, the following line sets the site name to EXPCONS: -S- EXPCONS

Typical Default Settings

Here are reasonable default settings for various machine configurations: •

For a small workstation with 64 MB memory and 1 GB of disk, the default algorithms and memory allocation are fine. MaxDisk is all that need be specified. -#- MaxDisk=400MB

•

On a powerful workstation with 8 processors and 1 GB of memory, being used for large jobs, all 8 processors should be used by default. Also, more memory should be given to each job: -M- 64MW -P- 8 -#- MaxDisk=10GB

User Defaults Files

Gaussian users may set their own defaults by creating their own Default.Route file. Gaussian checks the current working directory for a file of this name when a job is

initiated. Settings in the local file take precedence over those Gaussian 03 Online Manual Last update: 8 July 2004


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Gaussian has been designed to work efficiently given a variety of computer

configurations. In general, the program attempts to select the most efficient algorithm given the memory and disk constraints imposed upon it. Since Gaussian does offer a wide choice of algorithms, an understanding of the possibilities and tradeoffs can help you to achieve optimal performance. Before proceeding, however, let us emphasize two very important points: •

•

The default algorithms selected by the program give good performance for all but very large jobs. Note that some defaults have changed with Gaussian 03 to reflect current typical problem sizes. Defaults used in earlier versions of the program were designed for small jobs of under 100 basis functions. The default algorithms used in Gaussian are generally designed for longer jobs. For users or sites who routinely run very large jobs, the following defaults placed in the Default.Route file will produce good general performance: -M- available-memory -#- MaxDisk=available-disk

•

where the amount of available memory and disk are specified as indicated; the default units for each are 8-byte words, and either value may be followed by KB, MB, GB, KW, MW or GW (without intervening spaces) to specify units of kilo-, mega- or giga- bytes or words. Once the Default.Route file is set up, for many sites, no other special actions are required for overall efficient program use. The default memory size is 6MW.

Estimating Calculation Memory Requirements

The following formula can be used to estimate the memory requirement of various types of Gaussian jobs (in 8-byte words): M + 2 N B2

where NB is the number of basis functions used in the calculation, and M is a minimum value that depends on the job type, given in the following table:

Job Type

Highest Angular Momentum Basis Function f functions g functions h functions i functions j functions

SCF Energies SCF Gradients SCF Frequencies MP2 Energies

4 MW 4 MW 4 MW 4 MW

4 MW 5 MW 9 MW 5 MW


9 MW 16 MW 27 MW 10 MW

23 MW 38 MW

~60 MW

28 MW

~70 MW

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MP2 Gradients MP2 Frequencies

4 MW 6 MW

6 MW 10 MW

16 MW 28 MW

38 MW

For example, on a 32-bit system, a 300 basis function HF geometry optimization using g functions would require about 5.2 MW (~42 MB) of memory. Note that 1 MW = 1,048,576 words (= 8,388,608 bytes). The values in the table are for 32-bit computer systems; they would need to be doubled for 64-bit systems. They also reflect the use of uncontracted higher angular momentum functions-f and above-which is the default type. Larger amounts of memory may be required for derivatives of contracted high angular momentum functions. The remainder of this chapter is designed for users who wish to understand more about the tradeoffs inherent in the various choices in order to obtain optimal performance for an individual job, not just good overall performance. Techniques for both very large and small jobs will be covered. Additional, related information may be found in reference [572]. Memory Requirements for Parallel Calculations

When using multiple processors with shared memory, a good estimate of the memory required is the amount of memory from the preceding table for each processor. Thus, if the value from the table is 10 MW and you want to use four shared memory processors, set %Mem to be at least 40 MW. For distributed memory calculations (i.e., those performed via Linda), the amount of memory specified preceding table. in %Mem should be equal to or greater than the value from the In Gaussian 03, these two parallelization methods can be combined. For example, you would use the following directive in order to run a job on 8 CPUs located on four twoheaded shared memory multiprocessors (assuming that the memory value from the table is 10 MW): %Mem=20MW %NProcLinda=4 %NProcShared=2 computer.

Memory required by each multiprocessor. Use four Linda workers (one per multiprocessor). Use two shared memory processors on each multiprocessor

Storage, Transformation, and Recomputation of Integrals

One of the most important performance-related choices is the way in which the program processes the numerous electron repulsion integrals. There are five possible approaches to handling two-electron repulsion integrals implemented in Gaussian:


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AO

The two-electron integrals over the atomic orbitals (AO integrals) are generated once and stored externally on disk. This is the approach used by conventional SCF calculations. MO

The AO integrals are generated once and (MO) storedintegrals externally, to the This is molecular orbital basis. The transformed arethen alsotransformed stored externally. the approach used by earlier versions of Gaussian for all correlated energy methods. Direct

The AO integrals (and possibly integral derivatives) are recomputed as needed. This does not require O(N4) internal or external storage, but does potentially involve additional computational effort. In some cases, other savings are possible that compensate for this additional effort. In any case, direct methods are the only choice when memory and disk are exhausted and consequently are inevitably used for the largest calculations. In contrast to earlier versions of the program, the direct method is the default for SCF calculations in Gaussian . Semi-Direct

The AO integrals (and possibly integral derivatives) are recomputed as needed. In addition, MO quantities are stored temporarily on disk in whatever size chunks fit in the available disk space. In-Core

The AO integrals are generated once and stored in canonical order in main memory (i.e., including zeroes). This requires large amounts of memory, but allows the integrals to be processed using simple matrix operations and no I/O, and consequently is very fast. At least two of these approaches are available for all methods in Gaussian. The default method for a given job is chosen to give good performance on small to medium sized molecules. The various options and tradeoffs for each method are described in the following sections. SCF Energies and Gradients

The performance issues that arise for SCF calculations include how the integrals are to be handled, and which alternative calculation method to select in the event that the default procedure fails to converge. Integral Storage

By default, SCF calculations use the direct algorithm. It might seem that direct SCF would be preferred only when disk space is insufficient. However, this is not the case in practice. Because of the use of cutoffs, the cost of direct SCF scales with molecular size as N2.7 or better, while conventional SCF scales in practice as N3.5 [572]. Consequently, a point is reached fairly quickly where recomputing the integrals (really, only those


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integrals that are needed) actually consumes less CPU time than relying on external storage. Where this crossover occurs depends on how fast the integral evaluation in direct SCF is, and it varies from machine to machine. However, on modern computer systems, the most efficient strategy is to do an in-core SCF as long as it is feasible, and use the direct algorithm from that point on; the conventional algorithm is virtually never a good choice on such systems. The change to direct SCF as the default algorithm in Gaussian 98 was made in consideration of these facts. SCF=Conven keyword is only needed on small memory computer systems like obsolete PCs. In-core SCF is also available. Direct SCF calculations that have enough memory to store the integrals are automatically converted to in-core runs. SCF=InCore can be requested explicitly, in which case the job will be terminated if insufficient memory is available to store the integrals. Generally, about N4/8 + 500,000 words of memory are necessary for closed-shell in-core SCF, and N4/4 + 500,000 words for UHF or ROHF in-core SCF. This corresponds about 100 for MBa for 100 basis function job, 1.6 GB for a 200 basis function job,toand 8.1 GB 300abasis function job (closed-shell). GVB and MCSCF calculations can also be done using direct or in-core algorithms [405]. Memory requirements are similar to the open-shell Hartree-Fock case described above. The primary difference is that many Fock operators must be formed in each iteration. For GVB, there are 2Norb operators, where Norb is the number of orbitals in GVB pairs. For MCSCF, there are Nactive(Nactive-1)/2 + 1 operators, where Nactive is the number of orbitals in the active space. Consequently: •

•

Cutoffs are less effective than for Hartree-Fock, so the crossover in efficiency is at a larger number of basiscan functions. The number of operators be quite large for larger MCSCF active spaces, so performance can be improved by ensuring that enough memory is available to hold all the density and operator matrices at once. Otherwise, the integrals will be evaluated more than once per iteration.

Direct SCF Procedure

In order to speed up direct HF calculations, the iterations are done in two phases: •

•

The density is converged to about 10-5 using integrals accurate to six digits and a modest integration DFTconverged. calculations. This step is terminated after 21 iterations even if it grid is notinfully This step is omitted by default if any transition metal atoms are present. The density is then converged to 10-8 using integrals accurate to ten digits, allowing up to a total of 64 cycles total for the two steps.

This approach is substantially faster than using full integral accuracy throughout without slowing convergence in all cases tested so far. In the event of difficulties, full accuracy of


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the integrals throughout can be requested using SCF=NoVarAcc, at the expense of additional CPU time. See the discussion of the SCF keyword for more details. Single-Point Direct SCF Convergence

In order to improve performance for single-point modification of the default SCF approach is used:direct and in-core SCF calculations, a •

•

The integrals are done to only 10-6 accuracy except for all-electron (non-ECP) calculations involving molecules containing atoms heavier than argon. The SCF is converged to either 10-4 on both the energy and density, or to 10-5 on the energy, whichever comes first.

This is sufficient accuracy for the usual uses of single-point SCF calculations, including relative energies, population analysis, multipole moments, electrostatic potentials, and electrostatic potential derived charges. Conventional SCF single points and all jobs other -8

than single points use tight convergence on the density. The tighter convergence can be applied to single-point direct SCFofby10requesting . See the discussion SCF=Tight of the SCF keyword for more details. Problem Convergence Cases

The default SCF algorithm now uses a combination of two Direct Inversion in the Iterative Subspace (DIIS) extrapolation methods EDIIS and CDIIS. EDIIS [559] uses energies for extrapolation, and it dominates the early iterations of the SCF convergence process. CDIIS, which performs extrapolation based on the commutators of the Fock and density matrices, handles the latter phases of SCF convergence. This new algorithm is very reliable, troublesome SCF cases now almost always converge withand the previously default algorithm. For the fewconvergence remaining pathological convergence cases, Gaussian 03 offers Fermi broadening and damping in combination with CDIIS (including automatic level shifting). These are the available alternatives if the default approach fails to converge (labeled by their corresponding keyword): SCF=Fermi

Requests temperature broadening during early iterations [562], combined with CDIIS and dynamic damping of early SCF iterations. SCF=QC

This is quadratically convergent SCF, based on the method of Bacskay [563]. Since it combines linear minimizations with the Newton-Raphson algorithm suggested by Bacskay, it is guaranteed to reach a stationary point eventually. Typically, SCF=QC is about twice as expensive as conventional SCF. Since SCF=QC is reliable and can be used for direct SCF, it is usually the first choice if convergence problems are encountered. It can be used for RHF and UHF, but not for complex or ROHF.


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Guess=Alter

Sometimes convergence difficulties are a warning that the initial guess has occupied the wrong orbitals. The guess should be examined, especially as to the symmetries of the occupied orbitals. Guess=Alter can be used to modify the orbitals selected for occupation. SCF=NoDIIS

This implies conventional SCF using the old 3 and 4 point extrapolation. It is not usually a good choice for RHF and UHF, but is sometimes helpful for ROHF, for which there are fewer alternatives. More than 64 cycles may be needed for convergence. SCF=(MaxCyc= N )

Increases the total number of SCF iterations to N . Note that merely increasing the number of SCF cycles for the default algorithm is rarely helpful. SCF=DM

Thisbut is the steepest HF, notolder for direct HF descent or DFT.algorithm of Seeger [564]. It can be used for complex These approaches all tend to force convergence to the closest stationary point in the orbital space, which may not be a minimum with respect to orbital rotations. A stability calculation can be used to verify that a proper SCF solution has been obtained (see the Stable keyword). Note also that you should verify that the final wavefunction corresponds to the desired electronic state, especially when using Guess=Alter. SCF Frequencies

Four alternatives for integral processing are available for Hartree-Fock second derivatives: Direct

The coupled perturbed Hartree-Fock (CPHF) equations are solved using integrals that are recomputed every iteration. Since cutoffs are not as effective for direct CPHF as for direct SCF, the crossover to direct being faster is higher, but even for 100 basis functions, direct frequencies are only about 40% slower than conventional (AO). Hence, as for direct SCF, the direct algorithm is preferred above 100 basis functions or so on vector machines and must be used when disk is exhausted on scalar machines. This algorithm is the default. AO

The CPHF equations are solved using the written-out AO integrals. The petit (symmetry reduced) list can be used. This may be the optimal choice for jobs of up to about 100 basis functions. MO

The CPHF equations are solved using transformed integrals. This is the only method used


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in most other electronic structure programs and is a bit faster than using the AO basis for small cases, but it is basically a waste of disk space. It is selected by specifying CPHF=MO in the route section. This option is not available for DFT methods. In-Core

The are stored memory canonical order.method Memory requirements are the sameintegrals as for in-core SCF.inThis is theinfastest available when it can be used. This algorithm is selected using SCF=InCore. By default, during in-core frequencies, the integrals are computed once by each link that needs them. This keeps the disk storage down to the same modest amount as for directO(N3). If N4/8 disk is available, and in-core is being used only for speed, then specifying SCF=(InCore,Pass) will cause the integrals to be stored on disk (on the read-write file) after they are computed for the first time, and then read from disk rather than be recomputed by later steps. HF frequency calculations include prediction of the infrared and Raman vibrational but intensities by default. The IR intensities add negligible overhead to the calculation, the Raman intensities add 10-20%. If the Raman intensities are not of interest, they can be suppressed by specifying Freq=NoRaman. Freq=Raman produces Raman intensities by numerical differentiation for DFT and MP2

frequency calculations. Using this option does not change the calculation's disk requirements, but it will increase the CPU time for the job. Computing pre-resonance Raman intensities (with CPHF=RdFreq) will approximately double the job's CPU requirements. While frequency calculations bebe done using verybetter modest amountsmemory of memory, performance on very large jobscan will considerably if enough is available to complete the major steps in one pass. Link 1110 must form a "skeleton derivative Fock matrix" for every degree of freedom (i.e., 3 x Number-of-atoms) and if only some of the matrices can be held in memory, it will compute the integral derivatives more than once. Similarly, in every iteration of the CPHF solutions, link 1002 must form updates to all the derivative Fock matrices. Link 1110 requires 3NA N2/2 words of memory, plus a constant amount for the integral derivatives to run optimally. Link 1002 requires 3NA N2 words, plus a constant amount, to run optimally. The freqmem utility program returns the optimal memory size for different parameters of frequency calculation (i.e., the amount required to perform the major steps in a single pass). MP2 Energies

Four algorithms are available for MP2, but most of the decision-making is done automatically by the program. The critical element of this decision making is the value of MaxDisk , which should be set according to your particular system configuration (see


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chapter 3). It indicates the maximum amount of disk space available in words. If no value is specified for MaxDisk , either in the route section or in the Default.Route file, Gaussian will assume that enough disk is available to perform the calculation with no redundant work, which may not be the case for larger runs. Thus, specifying the amount of available memory and disk is by far the most important way of optimizing performance for MP2 calculations. Doing sothe allows the one program to decide between theconfiguration. various available algorithms, selecting optimal for your particular system This is best accomplished with -M- directive and MaxDisk keyword in the Default.Route

file (although MaxDisk and %Mem may be included in the input file). The algorithms available for MP2 energies are: Semi-Direct

The AO integrals are generated as needed. The half-transformed integrals (ip|λσ) over one or more occupied orbitals i are sorted on disk. This method can function in as little as O(N2) memory and N3 disk and is usually the optimal choice. It is specified with MP2=SemiDirect . In-Core

The AO integrals are generated once and stored in canonical order in memory. N4/4 memory is required. This is very fast if sufficient memory is available. This algorithm can be specified with MP2=InCore, which does in-core SCF and MP2. FullDirect

The AO integrals are recomputed as needed during evaluation of E(2). No external storage is required. The number of integral evaluations depends on the amount of memory available. This is a good method only for machines with large amounts of physical memory. It is specified with MP2=FullDirect . Conventional

The AO integrals are written out and transformed, then the MO integrals are antisymmetrized to produce E(2). This was the default algorithm in Gaussian 88 and earlier versions. The MP2=Conven keyword forces this conventional MP2 algorithm. While the new (semi-direct) algorithm can function well for very large N in modest memory, it does have a fixed minimum memory requirement of about one million words for basis sets containing only s, p, and d functions. The old code, which is slower on all machines, can be run in very small memory and may be needed on low-end machines. Use=L903 The AO integrals are written out, then the transformation and formation of E(2) are done

in memory. N3/2 memory is necessary. This was an option in Gaussian 88 if the energy but not the gradient was desired. This algorithm is selected with Use=L903. In addition, when the direct, semi-direct, and in-core MP2 algorithms are used, the SCF phase can be either conventional, direct, or in-core. The default is direct or in-core SCF.


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MP2 Gradients

The choices for MP2 gradients are much the same as for MP2 energies, except: •

•

•

The conventional algorithm requires the storage of the two-particle density matrix and considerably more diskfor than if only than energies arecorresponding needed. The newtherefore methods uses require no more disk space gradients for the energies. The modern methods compute the integral derivatives at least twice, once in the E2 phase and once after the CPHF step. As a result, for small systems (50 basis functions and below) on scalar machines, the conventional algorithm is somewhat faster. The integral derivative evaluation during E2 in the new algorithms requires extra main memory if higher than f functions are used.

As for the MP2 energy, the default is to do direct or in-core SCF and then dynamically 2

choose between semi-direct, direct, or in-core E . MP2 Frequencies

Only semi-direct methods are available for analytic MP2 second derivatives. These reduce the disk storage required below what a conventional algorithm requires. MP2 frequency jobs also require significant amounts of memory. The default of six million words should be increased for larger jobs. If f functions are used, eight million words should be provided for computer systems using 64-bit integers. Higher Correlated Methods

The correlation methods beyond MP2 (MP3, MP4, CCSD, CISD, QCISD, etc.) all require that some transformed (MO) integrals be stored on disk and thus (unlike MP2 energies and gradients) have disk space requirements that rise quartically with the size of the molecule. There are, however, several alternatives as to how the transformed integrals are generated, how many are stored, and how the remaining terms are computed: •

•

•

z$$f$$>The default in Gaussian is a semi-direct algorithm. The AO integrals may be written out for use in the SCF phase of the calculation or the SCF may be done directly or in-core. The transformation recomputes the AO integrals as needed and leaves only the minimum number of MO integrals on disk (see below). The remaining terms are computed by recomputing AO integrals. A full transformation is performed if MaxDisk supplies sufficient disk for doing so. This will be faster than other approaches unless the computer system's I/O is very slow. The conventional algorithm, which was the default in Gaussian 90, involves storing the AO integrals on disk, reading them back during the transformation, and forming all of the MO two-electron integrals except those involving four


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virtual orbitals. The four virtual terms were computed by reading the AO integrals. This procedure can be requested in Gaussian by specifying Tran=Conven in the route section. However, it is appropriate only on very slow machines like legacy PCs. If a post-SCF calculation can be is done using a full integral transformation keeping disk usage under MaxDisk , this done; if not, a partial transformation is while done and some terms are computed in the AO basis. Thus, it is crucial for a value for MaxDisk to be specified explicitly for these types of jobs, either within the route section or via a system wide setting in the Default.Route file. If MaxDisk is left unset, the program assumes that disk is abundant and performs a full transformation by default. If MaxDisk is not set and sufficient disk space is not available for a full transformation, the job will fail. The following points summarize the effect of MaxDisk for post-SCF methods: •

CID, CISD, CCD, BD, and QCISD energies also have a fixed storage requirement 2

•

•

2

storage proportional to O N , with a large factor, but obey MaxDisk in avoiding larger requirements. CCSD, CCSD(T), QCISD(T), and BD(T) energies have fixed disk requirements proportional to ON3 which cannot be limited by MaxDisk . CID, CISD, CCD, QCISD densities and CCSD gradients have fixed disk requirements of about N4/2 for closed-shell and 3N4/4 for open-shell.

Excited State Energies and Gradients

In addition to integral storage selection, the judicious use of the restart facilities can improve the economy of CIS and TD calculations. Integral Storage

Excited states using CI with single excitations can be done using five methods (labeled by their corresponding option to the CIS keyword). Note that only the first two options are available for the TD method: Direct

Solve for the specified number of states using iterative diagonalization, forming the product vectors from two-electron integrals computed as needed. This algorithm reduces memory and disk requirements to O(N2). InCore

Requests that the AO Raffenetti combinations be held in memory. In-core is quite efficient, but is only practical for small molecular systems or large memory computers as N4/4 words of memory are required. This approach is used automatically if there is sufficient memory available.


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MO

Solve for the specified number of states using iterative (Davidson) diagonalization, forming the product vectors using MO integrals. This is the fastest method and is the default. This algorithm is an efficient choice up to about 150 basis functions, depending on the number of occupied orbitals. The more occupied orbitals, the sooner the direct algorithm should be used.isSince integrals involving two virtuals arerequired needed is (even for gradients) an attempt madeonly to obey MaxDisk. The minimum disk about 2 2 2 2 4O N (6O N for open-shell). AO

Solve for the specified number of states using iterative diagonalization, forming the product vectors from written-out AO integrals. This is a slow method and is never the best choice. ICDiag

The entire CIS Hamiltonian matrix is loaded into core and diagonalized. This produces 2

2

3

3

all possible states, but requires O V memory andand O for V CPU time. Accordingly, practical only for very small molecular systems debugging purposes. it is Restarting Jobs and Reuse of Wavefunctions

CIS and TD jobs can be restarted from a Gaussian checkpoint file. This is of limited use for smaller calculations, which may be performed in the MO basis, as new integrals and transformation must be done, but is invaluable for direct CIS. If a direct CIS job is aborted during the CIS phase, then SCF=Restart should be specified in addition to CIS=Restart or TD=Restart, as the final SCF wavefunction is not moved to its permanent location (suitable for Guess=Read) until the entire job step (or optimization step) completes. CIS Excited State Densities

If only density analysis is desired, and the excited states have already been found, the CIS density can be recovered from the checkpoint file, using Density=(Check,Current) Guess=Only, which recovers whatever generalized density was stored for the current method (presumably CIS) and repeats the population analysis. Note that the one-particle (unrelaxed) density as well as the generalized (relaxed) density can be examined, but that dipole moments and other properties at the CIS level are known to be much less accurate if the one-particle density is used (i.e., if the orbital relaxation terms are neglected) [108,447]. Consequently, thethe usecorrect of thedensity CIS one-particle density is strongly except for comparison with and with other programs thatdiscouraged, cannot compute the generalized density. Separate calculations are required to produce the generalized density for several states, since a CPHF calculation must be performed for each state. To do this, first solve for all the states and the density for the first excited state:


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# CIS=(Root=1,NStates=N) Density=Current

if N states are of interest. Then do N -1 additional runs, using a route section of the form: CIS=(Read,Root=M,NStates=N) Density=Current

for states M =2 through N . Pitfalls for Open-Shell Excited States

Since the UHF reference state is not an eigenfunction of S2, neither are the excited states produced by CIS or TD [573]. Stability Calculations

Tests of Triplet and Singlet instabilities of RHF and UHF and restricted and unrestricted MO, AO, Direct, DFTInCore wavefunctions can available, be requested using the Stable keyword. Thealgorithm. and options are which request the corresponding The default is Direct. Direct stability calculations can be restarted as described above for CIS.

CASSCF Efficiency

The primary challenge in using the CASSCF method is selecting appropriate active space orbitals. There are several possible tactics: •

•

•

Use the standard delocalized initial guess orbitals. This is sometimes sufficient, Guess=Only to inspect the e.g. if theand active space consists p electrons. orbitals determine whether of anyallalterations areUse required before running the actual calculation. Use localized initial guess orbitals. This is useful if specific bond pairs are to be included, since localization separates electron pairs. Use the natural orbitals from the total density from a UHF calculation (CASUNO) [415,416]. For singlets, this requires that one has coaxed the UHF run into converging to a broken symmetry wavefunction (normally with Guess=Mix). It is most useful for complex systems in which it is not clear which electrons are most poorly described by doubly-occupied orbitals.

In cases, a single-point calculation before any optimization, so thatallthe converged active space can beshould checkedbetoperformed ensure that the desired electrons have been correlated before proceeding. There are additional considerations in solving for CASSCF wavefunctions for excited states (see the discussion of the CASSCF keyword for details). CASSCF Frequencies


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CASSCF frequencies require large amounts of memory. Increasing the amount of available memory will always improve performance for CASSCF frequency jobs (the same is not true of frequency calculations performed with other methods). These calculations also require O2 N2 disk space.

Running Gaussian Test Jobs An extensive set of test jobs for Gaussian are provided, along with their corresponding output files. The input files are found in directory $g03root/g03/tests/com. Output files are in a separate subdirectory under $g03root/g03/tests for each machine, such as tests/rs6k for the RS/6000 files. A command file is provided which runs ranges of test jobs automatically (described below). If you build the program from source code, we recommend that you run a few of the test jobs to verify that the program has been built correctly. However, it is not usually necessary to run the entire test suite. You do not need to run test jobs for binary distributions. Test job input files have names of the form testnnn.com. Tests 1, 28, 94, 155, 194, 296, and 302 cover a range of Gaussian capabilities. Note that some test jobs are intended for fast hardware and are quite expensive on smaller, slower computer systems. The file $g03root/g03/tests/tests.id x lists what each test job does, and the reference output files provided with Gaussian indicate how long the jobs can be expected to take. You can extract this information using the following commands: $ cd $g03root/g03/tests/`gau-machine` $ grep "cpu time" *.log

The utility gau-machine returns the system name on all UNIX platforms (i.e., a keyword corresponding to the type of computer on which you are running). Rename Existing Default.Route File Before Running Test Jobs

If you choose to run some or all of the Gaussian test jobs, you will need to make sure that they run with the program's built-in default settings. Therefore, you'll need to rename both the site-wide Default.Route file (located in the $g03root/g03 directory) as well as any individual version of the defaults file that you may have prior to running any test job. Note that certain settings in this file can cause some test jobs to fail. Examples •

The script submit.csh can be used to run test jobs. It accepts two parameters: the numbers of the first and last jobs to run (by default, all of the tests are run). Note that you should run the test jobs from a separate directory to prevent them from clobbering the reference output.


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•

The following commands illustrate the recommended procedure for running a test job, using the directory /chem/newtests as the test job executor area and test job 28 as an example:

$ mkdir /chem/newtests; cd /chem/newtests $ ln -s $g03root/g03/tests/com . $ mkdir `gau-machine` $ $g03root/g03/tests/submit.csh m n &

The final command runs test m through n. After each test job finishes, verify that it completed successfully. Then, compare its current output with the reference output using the d1 script. For example: $ $g03root/g03/tests/d1 m n

The d1 script filters out insignificant differences from the output files for test jobs m through n and pipes the remaining output through more. The differences that appear should be limited to non-substantive items.

This page outlines the various size limitations that exist within Gaussian 03. These limitations occur in the form of fixed dimension statements and algorithm design limitations, and their overall effect is to limit the size and types of calculation that can be performed. Z-matrix Limitations

There are restrictions on the size of a Z-matrix, the maximum number of variables and the maximum number of atoms within a calculation. These are set consistently for a maximum of 20000 real atoms (including ghost but not dummy atoms), and a maximum of 20000 Z-matrix centers (atoms, ghost atoms, and dummy atoms). In addition, the maximum number of variables that can be specified in an optimization is unlimited for Berny optimizations but must not exceed 50 for Murtaugh-Sargent or Opt=EF optimizations (30 for Fletcher-Powell optimizations). Basis Set Limitations

Throughout the Gaussian setthe limitations manifest themselves in two ways. The main restriction 03 is system, imposedbasis within integral evaluation programs and limits the number of primitive gaussian functions and how they are combined into atomic orbital basis functions. Secondly, dimensioning requirements limit the total number of basis functions that can be used in a few of the older of the energy evaluation procedures.


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Integral Program Limitations

To understand fully the limitations in the integral programs, the reader must have some understanding of the concepts presented in discussion of the Gen keyword (input of nonstandard bases). In the terminology introduced there, the limitations are as follows: the maximum number of primitive shellsofisprimitive 60000; the maximum number of primitive d-shells is total 20000; the maximum number f-shells and higher is 20000; the maximum number of contracted shells is 20000. The maximum degree-of-contraction allowed is 100. The other major restriction that appears in the integral programs is in the manner in which integral labels are packed. These limits apply only when two-electron integrals are written out and can be avoided entirely by using SCF=Direct (which is the default in Gaussian 03). Normally, disk space limitations force the use of direct methods before the following limits are reached. When conventional integralthestorage procedure is selected contrast to integral the Raffenetti ("PK")the storage modes [574]), suffixes μ, ν, λ, and σ of the(in two-electron (μν| λσ) are packed into a computer word as 8-bit quantities in the UNIX version, and as 16 bit quantities in the UniCOS version. This in effect limits the number of basis functions to 255 under UNIX for conventional calculations in this mode. When the Raffenetti modes are selected (for SCF=Conventional except when Tran=Conventional, Stable=Complex, or CASSCF is also specified), the two linearized suffixes (μν) and (λσ) (where (μν=(μ(μ-1)/2)+ν) are packed into a word. This imposes a theoretical limit of 361 basis functions for conventional calculations on the 32-bit computer systems. These limits do not apply to direct calculations. SCF and Post-SCF Limitations

There are only a few other links which have additional dimensioning limits. There is no further restriction for RHF, UHF, ROHF, DFT, MP, CI, QCISD, CC, or BD calculations using the default algorithms. Complex HF calculations are limited to 180 basis functions, and complex MP2 calculations are effectively limited by a requirement of O(N3) words of main memory, and are also limited to f functions. The GVB program is limited to 100 paired orbitals, which is not a restriction in practice. The remaining restrictions are in some of alternative programs which must be specifically requested. SCF=DM is limited to 255 basis functions, although the preferred SCF=QC can be used with direct SCF and imposes no dimensioning limits. Link 903 (in-core MP2) requires O(N3) words of main memory. NBO Dimensions

NBO is dimensioned for 200 atoms and 10000 basis functions.


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Gaussian 03 input consists of a series of lines in an ASCII text file. The basic structure of a Gaussian input file includes several different sections: • •

• •

•

Link 0 Commands: Locate and name scratch files (not blank line terminated). Route section (# lines): Specify desired calculation type, model chemistry and

other options (blank line terminated). Title section: Brief description of the calculation (blank line terminated). Molecule specification: Specify molecular system to be studied (blank line terminated). Optional additional sections: Additional input needed for specific job types (usually blank line terminated).

Many Gaussian 03 jobs will include only the second, third, and fourth sections. Here is an example of such a file, which requests a single point energy calculation on water: # HF/6-31G(d)

Route section

water energy 0 1 O -0.464 0.177 H -0.464 1.137 H 0.441 -0.143

Title section Molecule specification 0.0 0.0 0.0

In this job, the route and title sections each consist of a single line. The molecule specification section begins with a line giving the charge and spin multiplicity for the molecule: 0 charge (neutral molecule) and spin multiplicity 1 (singlet) in this case. The charge and spin multiplicity line is followed by lines describing the location of each atom in the molecule; this example uses Cartesian coordinates to do so. Molecule specifications are discussed in more detail later in this chapter. The following input file illustrates the use of Link 0 commands and an additional input section: %Chk=heavy #HF/6-31G(d) Opt=ModRedundant

Link 0 section Route section

Opt job

Title section

0 1 atomic coordinates …

Molecule Specification section

3 8 2 1 3 opt.

Add a bond and an angle to the internal coordinates used during the geom.

This job requests a geometry optimization. The input section following the molecule specification is used by the Opt=ModRedundant keyword, and it serves to add an


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additional bond and angle in the internal coordinates used in the geometry optimization. The job also specifies a name for the checkpoint file. Link 0 commands were introduced in the last chapter and are discussed individually in the penultimate section of this chapter. The remaining input sections are discussed in the subsequent this introductory For convenience, tablewith below all possible subsections sections thatofmight appear withinsection. a Gaussian 03 input file,the along the lists keywords associated with each one.

In general, Gaussian input is subject to the following syntax rules: Input is free-format and case-insensitive. Spaces, tabs, commas, or forward slashes can be used in any combination to separate items within a line. Multiple spaces are treated as a single delimiter. Options to keywords may be specified in any of the following forms:

• •

•

keyword = option keyword (option) keyword=(option1, option2, ...) keyword (option1, option2, ...)

Multiple options are enclosed in parentheses and separated by any valid delimiter (commas are conventional and are shown above). The equals sign before the opening parenthesis may be omitted, or spaces may optionally be included before and/or after it.

•

•

•

•

Note some options also takeCBSExtrap values; in this case, the by anthat equals sign: for example, (NMin=6 ). option name is followed All keywords and options may be shortened to their shortest unique abbreviation within the entire Gaussian 03 system. Thus, the Conventional option to the SCF keyword may be abbreviated to Conven, but not to Conv (due to the presence of the Convergence option). This holds true whether or not both Conventional and Convergence happen to be valid options for any given keyword. The contents of an external file may be included within a Gaussian 03 input file using the following syntax: @ filename. This causes the entire file to be placed at the current location in the input stream. Appending /N to such commands will prevent the included file's contents from being echoed at the start of the output

•

file. Comments begin with an exclamation point (!), which may appear anywhere on a line. Separate comment lines may appear anywhere within the input file.

Gaussian 03 Input Section Ordering Section

Keywords


Final blank line?

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Link 0 commands Route Section (# lines) Extra Overlays Title section

% commands

all ExtraOverlays

all

Molecule specification all Modifications to coordinates Opt=ModRedundant Connectivity specifications Geom=Connect or ModConnect 2nd title and molecule specification Opt=QST2 or QST3 Modifications to 2nd set of Opt=ModRedun and QST2 or coordinates QST3 Connectivity specifications for 2nd Geom=Connect or ModConnect set and Opt=ModRedun and QST2 or of coordinates 3rd title and initial TS structure Modifications to 3rd set of coordinates Connectivity specifications for 3rd set of coordinates Atomic masses Frequency of interest Initial force constants (Cartesian) Accuracy of energy & forces BOMD/ADMP input (1 or more sections) Basis set specification Basis set alterations

no yes yes yes yes yes yes yes yes

yes

QST3 Opt=QST3

yes for both

Opt=(ModRedun, QST3)

yes

Geom=Connect or ModConnect

CPHF=RdFreq

yes yes yes

Opt=FCCards Opt=ReadError

yes no

ADMP and BOMD

yes

Gen, GenECP, ExtraBasis

yes yes

Opt=(ModRedun, QST3) IRC=ReadIsotopes

Massage

ECP specification

ExtraBasis, Pseudo=Cards, GenECP

yes

Density fitting basis set specification

Extra Density Basis

yes

Background charge distribution Finite field coefficients Symmetry types to combine Orbital specifications (separate α & β) Orbital alterations (separate α & β)

Charge Field=Read Guess=LowSymm

yes yes no

Guess=Cards

yes

Guess=Alter

yes


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Orbital reordering (separate α & β) PCM solvation model input Filename for COSMO/RS Weights for CAS state averaging

Guess=Permute

CASSCF=StateAverage

no yes no no

States of interest for spin orbit coupling # Orbitals/GVB pair Alternate atomic radii Data for electrostatic properties Cube filename (& Cards input) NBO input Orbital freezing information OVGF orbitals to refine Temperature, pressure, atomic masses PROAIMS/Pickett output filename

CASSCF=Spin

no

GVB

OVGF=ReadOrbitals

no yes yes yes no yes yes

Freq=ReadIsotopes

no

Output=WFN or Pickett

no

SCRF=Read SC RF=COSMORS

Pop=ReadRadii or ReadAtRadii Prop=Read or Opt Cube Pop=NBORead ReadWindow options

The route section of a Gaussian 03 input file specifies the type of calculation to be performed. There are three key components to this specification: • • •

type The job method The basis set

The following table lists the job types available in Gaussian 03: • • • • •

SP Single point energy. Opt Geometry optimization. Freq Frequency and thermochemical analysis. IRC Reaction path following. IRCMax Find the maximum energy along a specific reaction path.

• • • • • • • • •

Scan energyand surface scan. Polarizabilities hyperpolarizabilities. Polar Potential ADMP and BOMD Direct dynamics trajectory calculation. Force Compute forces on the nuclei. Stable Test wavefunction stability. Volume Compute molecular volume. Density=Checkpoint Recompute population analysis only. Guess=Only Print initial guess only; recompute population analysis. ReArchive Extract archive entry from checkpoint file only.


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In general, only one job type keyword should be specified. The exceptions to this rule are: •

•

Polar and Opt may be combined with Freq (although SCRF may not be combined with Opt Freq). In the latter case, the geometry optimization is

automatically followedwith by a IRCMax frequencyincalculation at the optimized Opt may be combined order to specify options forstructure. the optimization portion of the calculation.

When no job type keyword is specified within the route section, the default calculation type is usually a single point energy calculation ( SP). However, a route section of the form: method 2/basis2 // method 1/basis1 may be used to request an optimization calculation (at method 1/basis1) followed by a single point energy calculation (at method 2/basis2) at the optimized geometry. For example, the following route section requests a HF/6-31G(d) geometry optimization followed by a single point energy calculation using the QCISD/6-31G(d) model chemistry: # QCISD/6-31G(d)//HF/6-31G(d) Test

In this case, the Opt keyword is optional and is the default. Note that Opt Freq calculations may not use this syntax. Predicting Molecular Properties The following table provides a mapping between

commonly-desired predicted quantities and the Gaussian 03 keywords that will produce them: •

Atomic charges: Pop

• • • • • • •

Dipole moment: Electron affinitiesPop via propagator methods: OVGF Electron density: cubegen Electronic circular dichroism: TD Electrostatic potential: cubegen, Prop Electrostatic-potential derived charges: Pop=Chelp, ChelpG or MK Frequency-dependent polarizabilities/hyperpolarizabilities: Polar CPHF=RdFreq

• • • • • • • • • • • •

High accuracy energies: CBS-QB3, G2, G3, W1U Hyperfine coupling constants (anisotropic): Prop Hyperfine spectra tensors (incl. g tensors): Freq=(VCD, VibRot[, Anharmonic]) Hyperpolarizabilities: Freq, Polar Ionization potentials via propagator methods: OVGF IR and Raman spectra: Freq Pre-resonance Raman spectra: Freq CPHF=RdFreq Molecular orbitals: Pop=Regular Multipole moments: Pop NMR shielding and chemical shifts: NMR NMR spin-spin coupling constants: NMR =SpinSpin Optical rotations: Polar=OptRot CPHF=RdFreq


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• • • • •

Polarizabilities: Freq, Polar Thermochemical analysis: Freq UV/Visible spectra: CIS, Zindo, TD Vibration-rotation coupling: Freq=VibRot Vibrational circular dichroism: Freq=VCD

The combination of method and basis set specifies a model chemistry to Gaussian, specifying the level of theory. Every Gaussian job must specify both a method and basis set. This is usually accomplished via two separate keywords within the route section of the input file, although a few method keywords imply a choice of basis set. The following table lists methods which are available in Gaussian, along with the job types for which each one may be used. Note that the table lists only analytic optimizations, frequencies, and polarizability calculations; numerical calculations are often available for unchecked methods (see the discussion of the specific keyword in question for details).


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If no method keyword is specified, HF is assumed. Most method keywords may be prefaced by R for closed-shell restricted wavefunctions, U for unrestricted open-shell wavefunctions, or RO for restricted open-shell wavefunctions: for example, ROHF, UMP2, or RQCISD. RO is available only for Hartree-Fock, all Density Functional methods, AM1, MINDO3 and MNDO and PM3 semi-empirical energies and gradients, and MP2 energies; note that analytic ROMP2 gradients are not yet available. In general, only a single method keyword should be specified , and including more than one of them will produce bizarre results. However, there are exceptions: •

•

•

CASSCF may be specified along with MP2 to request a CASSCF calculation

including electron correlation. ONIOM and IRCMax jobs require multiple method specifications. However, they are given as options to the corresponding keyword. The form model 2 // model 1 described previously may be used to generate an automatic optimization followed by a single point calculation at the optimized geometry.

Most methods require a basis set be specified; if no basis set keyword is included in the route section, then the STO-3G basis will be used. The exceptions consist of a few methods for which the basis set is defined as an integral part of the method; they are listed below: • • •

All semi-empirical methods, including ZINDO for excited states. All molecular mechanics methods. Compound model chemistries: all Gn, CBS and W1 methods.

The following basis sets are stored internally in the Gaussian 03 program (see references cited for full descriptions), listed below by their corresponding Gaussian 03 keyword (with two exceptions): • • • • • •

•

STO-3G [309,310] 3-21G [311,312,313,314,315,316] 6-21G [311,312] 4-31G [317,318,319,320] 6-31G [317,318,319,320,321,322,323,324,325,326]

6-31G†: Gaussian 03 also includes the 6-31G† and 6-31G†† basis sets of George Petersson and coworkers, defined as part of the Complete Basis Set methods [88,327]. These are accessed via the 6-31G(d') and 6-31G(d',p') keywords, to which single or double diffuse functions may also be added; f functions may also be added: e.g., 6-31H(d'f), and so on. 6-311G: Specifies the 6-311G basis for first-row atoms and the McLean-Chandler (12s,9p) (621111,52111) basis sets for second-row atoms [328,329] (note that the basis sets for P, S, and Cl are those called "negative ion" basis sets by McLean


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and Chandler; these were deemed to give better results for neutral molecules as well), the basis set of Blaudeau and coworkers for Ca and K [322], the WachtersHay [330,331] all electron basis set for the first transition row, using the scaling factors of Raghavachari and Trucks [332], and the 6-311G basis set of McGrath, Curtiss and coworkers for the other elements in the third row [324,333,334]. Note

• • •

• • • •

•

•

•

• •

•

that Raghavachari andthe Trucks recommend bothsetscaling andtransition includingrow diffuse functions when using Wachters-Hay basis for first elements; the 6-311+G form must be specified to include the diffuse functions. MC-311G is a synonym for 6-311G. D95V: Dunning/Huzinaga valence double-zeta [335]. D95: Dunning/Huzinaga full double zeta [335]. SHC: D95V on first row, Goddard/Smedley ECP on second row [335,336]. Also known as SEC. CEP-4G: Stevens/Basch/Krauss ECP minimal basis [337,338,339]. CEP-31G: Stevens/Basch/Krauss ECP split valance [337,338,339]. CEP-121G: Stevens/Basch/Krauss ECP triple-split basis [337,338,339]. Note there is one CEPfor basis setatoms. defined beyond the second row, and all three that keywords areonly equivalent these LanL2MB: STO-3G [309,310] on first row, Los Alamos ECP

plus MBS on Na-

Bi [340,341,342]. LanL2DZ: D95V on first row [335], Los Alamos ECP plus DZ on Na-Bi [340,341,342]. SDD: D95V up to Ar [335] and Stuttgart/Dresden ECPs on the remainder of the periodic table [343,344,345,346,347,348,349,350,351,352,353,354,355,356,357,358,359,360,36 1,362,363,364,365,366,367]. The SDD, SHF, SDF, MHF, MDF, MWB forms may be used to specify these basis sets/potentials within Gen basis input. Note that the number of core electrons must be28 specified following the form (e.g., MDF28 for the MDF potential replacing core electrons). SDDAll: Selects Stuttgart potentials for Z > 2. cc-pVDZ, cc-pVTZ, cc-pVQZ, cc-pV5Z, cc-pV6Z: Dunning's correlation consistent basis sets [368,369,370,371,372] (double, triple, quadruple, quintuplezeta and sextuple-zeta, respectively). These basis sets have had redundant functions removed and have been rotated [373] in order to increase computational efficiency. These basis sets include polarization functions by definition. The following table lists the valence polarization functions present for the various atoms included in these basis sets:

Atoms cc-pVDZ cc-pVTZ

cc-pVQZ

H He B-Ne Al-Ar

4s,3p,2d,1f 5s,4p,3d,2f,1g 4s,3p,2d,1f 5s,4p,3d,2f,1g 5s,4p,3d,2f,1g 6s,5p,4d,3f,2g,1h 6s,5p,3d,2f,1g 7s,6p,4d,3f,2g,1h

2s,1p 2s,1p 3s,2p,1d 4s,3p,1d

3s,2p,1d 3s,2p,1d 4s,3p,2d,1f 5s,4p,2d,1f


cc-pV5Z

cc-pV6Z

6s,5p,4d,3f,2g,1h not available 7s,6p,5d,4f,3g,2h,1i not available

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Ga-Kr 5s,4p,1d 6s,5p,3d,1f not available not available not available These basis sets may be augmented with diffuse functions by adding the AUG prefix to the basis set keyword (rather than using the + and ++ notation-see below). However, the elements He, Mg, Li, Be, and Na do not have diffuse functions defined within these basis sets. SV, SVP, TZV and TZVP of Ahlrichs and coworkers [374,375]. MIDI! of Truhlar and coworkers [376]. The MidiX keyword is used to request this basis set. EPR-II and EPR-III: The basis sets of Barone [377] which are optimized for the computation of hyperfine coupling constants by DFT methods (particularly B3LYP). EPR-II is a double zeta basis set with a single set of polarization functions and an enhanced s part: (6,1)/[4,1] for H and (10,5,1)/[6,2,1] for B to F. EPR-III is a triple-zeta basis set including diffuse functions, double d polarizations and a single set of f-polarization functions. Also in this case the s part is improved to better describe the nuclear region: (6,2)/[4,2] for H and (11,7,2,1)/[7,4,2,1] for B to F. UGBS, UGBS1P, UGBS2P and UGBS3P: The universal Gaussian basis set of de Castro, Jorge and coworkers [378,379,380,381,382,383,384,385,386]. The latter three keyword forms have an additional 1, 2 or three polarization functions for each function in the normal UGBS basis set (i.e., UGBS1P adds a p function for each s, a d function for each p and so on; UGBS2P adds a p and d function for each s, a d and f function for each p, and UGBS3P adds a p, d and f for each s, etc.). MTSmall of Martin and de Oliveira, defined as part of their W1 method (see the W1U keyword) [94]. The DGDZVP, DGDZVP2 and DGTZVP basis sets used in DGauss [387,388]. •

• •

•

•

•

•

Adding Polarization and Diffuse Functions

Single first polarization functions can also be requested using the usual * or ** notation. Note that (d,p) and ** are synonymous-6-31G** is equivalent to 6-31G(d,p), for example-and that the 3-21G* basis set has polarization functions on second row atoms only. The + and ++ diffuse functions [389] are available with some basis sets, as are multiple polarization functions [390]. The keyword syntax is best illustrated by example: 6-31+G(3df,2p) designates the 6-31G basis set supplemented by diffuse functions, 3 sets of d functions and one set of f functions on heavy atoms, and supplemented by 2 sets of p functions on hydrogens. When the AUG- prefix is used to add diffuse functions to the cc-pV*Z basis sets, one diffuse function of each function type in use for a given atom is added [368,369]. For example, the AUG-cc-pVTZ basis places one s, one d, and one p diffuse functions on hydrogen atoms, and one d, one p, one d, and one f diffuse functions on B through Ne and Al through Ar. Adding a single polarization function to 6-311G (i.e. 6-311G(d)) will result in one d function for first and second row atoms and one f function for first transition row atoms,


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since d functions are already present for the valence electrons in the latter. Similarly, adding a diffuse function to the 6-311G basis set will produce one s, one p, and one d diffuse functions for third-row atoms. When a frozen-core calculation is done using the D95 basis, both the occupied core orbitals arecalculation frozen. Thus while a D95 ** calculation on waterand hasthe 26 corresponding basis functions,virtual and a orbitals 6-31G** on the same system has 25 functions, there will be 24 orbitals used in a frozen-core post-SCF calculation involving either basis set. The following table lists polarization and diffuse function availability and the range of applicability for each built-in basis set in Gaussian 03: Polarization Functions

Basis Set

Applies to

STO-3G

H-Xe * H-Xe * or ** H-Cl (d) H-Ne (d) or (d,p) H-Kr (3df,3pd) H-Kr (3df,3pd) H-Cl except Na and Mg (3df,3pd) H-Ne (d) or (d,p) H-Cl *

3-21G 6-21G 4-31G 6-31G 6-311G D95 D95V SHC

LanL2DZ

H-Rn H-Rn H-Rn H-Ba, La-Bi H, Li-Ba, La-Bi

SDD, SDDAll

all but Fr and Ra

CEP-4G CEP-31G CEP-121G LanL2MB

cc-pV(DTQ5)Z cc-pV6Z

Diffuse Functions

+

++ ++

++ ++

* (Li-Ar only) * (Li-Ar only) * (Li-Ar only)

H-He, B-Ne, Al-Ar, Gaadded via AUGincluded in definition Kr prefix added via AUGH, B-Ne included in definition

H-Kr H-Kr SVP TZV and TZVP H-Kr MidiX H, C-F, S-Cl, I, Br EPR-II, EPR-III H, B, C, N, O, F

prefix

SV

included in definition included in definition included in definition included in definition


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DGDZVP2

H-Lr H-Ar H-Xe H-F, Al-Ar, Sc-Zn

DGTZVP

H, C-F, Al-Ar

UGBS MTSmall DGDZVP

UGBS(1,2,3)P

Additional Basis Set-Related Keywords

The following additional keywords are useful in conjunction with these basis set keywords: • •

5D and 6D: Use 5 or 6 d functions (pure vs. Cartesian d functions), respectively. 7F and 10F: Use 7 or 10 f functions (pure vs. Cartesian f functions), respectively.

These keywords also apply to all higher functions (g and beyond). Other basis sets may also be input to the program using the ExtraBasis and Gen keywords. The ChkBasis keyword indicates that the basis set is to read from the checkpoint file (defined via the %Chk command). See the individual descriptions of these keywords later in this chapter for details. Issues Arising from Pure vs. Cartesian Basis Functions

Gaussian users should be aware of the following points concerning pure vs. Cartesian

basis functions: •

•

•

All of the built-in sets6-21G, use pure f functions. also6-31G††, use pure CEP-31G, d functions; the exceptions arebasis 3-21G, 4-31G, 6-31G, Most 6-31G†, D95 and D95V. The preceding keywords may be used to override the default pure/Cartesian setting. Note that basis functions are generally converted to the other type automatically when necessary, for example, when a wavefunction is read from the checkpoint file for use in a calculation using a basis consisting of the other type [391]. Within a job, all d functions must be 5D or 6D, and all f and higher functions must be pure or Cartesian. When using the ExtraBasis, Gen and GenECP keywords, the basis set explicitly specified in the route section always determines the default form of the basis 5Dthe 7F). For functions , these are and3-21G if you a general basis set taking (for someGen functions from and example, 6-31G basis sets,use pure functions will be used unless you explicitly specify 6D in the route section in addition to Gen. Similarly, if you add basis functions for a transition metal from the 6311G(d) basis set via ExtraBasis to a job that specifies the 6-31G(d) basis set in the route section, Cartesian d functions will be used. Likewise, if you want to add basis functions for Xe from the 3-21G basis set to the 6-311 basis set via the ExtraBasis keyword, the Xe basis functions will be pure functions.


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Density Fitting Basis Sets

Gaussian 03 provides the density fitting approximation for pure DFT calculations [35,36,392]. This approach expands the density in a set of atom-centered functions when computing the Coulomb interaction instead of computing all of the two-electron integrals. It provides performance purescaling DFT calculations on medium sized systems toosignificant small to take advantagegains of thefor linear algorithms without a significant degradation in the accuracy of predicted structures, relative energies and molecular properties. Gaussian 03 can generate an appropriate fitting basis automatically from the AO basis, or you may select one of the built-in fitting sets. The desired fitting basis set is specified as a third component of the model chemistry, as in this example: # BLYP/6-31G(d)/Auto

Note that the slashes are required when a density fitting basis set is specified. The DGA1 and DGA2 fitting sets [387,388] are available in Gaussian. DGA1 is available for H through Xe, and DGA2 is available for H, He and B through Ne. In addition, density fitting sets can be generated automatically from the AO primitives using Auto, Auto=All, or Auto= N . In the latter case, N is the maximum angular momentum retained in the fitting functions. The default is Max(MaxTyp+1,2*MaxVal ), where MaxTyp is the highest angular momentum in the AO basis and MaxVal is the highest valence angular momentum. PAuto generates all products of AO functions on one center instead of just squares of the AO primitives, but this is typically more functions than are needed. By default, no fitting set is used. Density fitting basis sets may be augmented with the ExtraDensityBasis keyword, defined in full with the Gen keyword, and optionally retrieved from the checkpoint file (use ChkBasis to do so).

The Job Title Section This section is required in the input, but is not interpreted in any way by the Gaussian 03 program. It appears in the output for purposes of identification and description. Typically, this section might contain the compound name, its symmetry, electronic state, other relevant information. The title section cannot exceed fivethe lines and must be and any followed by a terminating blank line. Since archive entries resulting from calculations using a general basis set or the ReadWindow keyword do not contain the original input data for these options, it is strongly recommended that the title sections for these jobs include a complete description of the basis set or frozen-core selection used.


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The following characters should be avoided in the title section: @ # ! - _ \ all control characters, and especially ^G.

This input section specifies the nuclear positions and the number of electrons of α- and βspin. There are several ways in which the nuclear configuration can be specified: as a Zmatrix, as Cartesian coordinates, or as a mixture of the two (note that Cartesian coordinates are just a special case of the Z-matrix). The first line of the molecule specification section specifies the net electric charge (a signed integer) and the spin multiplicity (a positive integer). Thus, for a neutral molecule in a singlet state, the entry 0 1 is appropriate. For a radical anion, -1 2 would be used. This is the only molecule specification input required if Geom=CheckPoint is used. The entire molecule specification (and title section) may be omitted by including Geom=AllCheck in the route section. The remainder of the molecule specification gives the element type and nuclear position for each atom in the molecular system. The most general format for the line within it is the following: Element-label [– Atom-type[–Charge]][( param=value[, ...])] Atom-position-parameters

Each line contains the element type, and possibly an optional molecular mechanics atom type and partial charge. Nuclear parameters for this atoms are specified in the parenthesized list. The remainder of the line contains information about the atom's location, either as Cartesian coordinates or as a Z-matrix definition. We'll begin by considering the initial and final items, and then go on to discuss the remaining items. The following are the basic formats for specifying atoms within the molecule specification (omitting all of the optional items): Element-label x y z Element-label [n] atom1 bond-length atom2 bond-angle atom3 dihedral-angle [ format-code]

Although these examples use spaces to separate items within a line, any valid separator may be used. The first form specifies the atom in Cartesian coordinates, while the second uses internal coordinates. Lines of both types may appear within the same molecular specification. optional format-code parameter in the second line is specifies of the Z-matrixThe input. For the syntax being described here, this code always the 0. Itformat is needed only when additional parameters follow the normal data, as in an ONIOM calculation. n is an optional parameter related to freezing atoms during optimizations using ONIOM or (rarely) ones not performed using redundant internal coordinates (see ONIOM for details).


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Element-label is a character string consisting of either the chemical symbol for the atom

or its atomic number. If the elemental symbol is used, it may be optionally followed by other alphanumeric characters to create an identifying label for that atom. A common practice is to follow the element name with a secondary identifying integer: C1, C2, C3, and so on; this technique is useful in following conventional chemical numbering. In the first form, the remaining items on each line are Cartesian coordinates specifying the position of that nucleus. In the second form, atom1, atom2, atom3 are the labels for previously-specified atoms which will be used to define the current atoms' position (alternatively, the other atoms' line numbers within the molecule specification section may be used for the values of variables, where the charge and spin multiplicity line is line 0). The position of the current atom is then specified by giving the length of the bond joining it to atom1, the angle formed by this bond and the bond joining atom1 and atom2, and the dihedral (torsion) angle formed by the bond joining atom2 and atom3 with the plane containing the current atom, atom1 and atom2. Here are two molecule specification sections for ethane: 0 C C H H H H H H

1 0.00 0.00 1.02 -0.51 -0.51 -1.02 0.51 0.51

0.00 0.00 0.00 -0.88 0.88 0.00 -0.88 0.88

0.00 1.52 -0.39 -0.39 -0.39 1.92 1.92 1.92

0,1 C1 C2,C1,1.5 H3,C1,1.1,C2,111.2 H4,C1,1.1,C2,111.2,H3,120. H5,C1,1.1,C2,111.2,H3,-120. H6,C2,1.1,C1,111.2,H3,180. H7,C2,1.1,C1,111.2,H6,120. H8,C2,1.1,C1,111.2,H6,-120.

The version on the left uses Cartesian coordinates while the one on the right represents a sample Z-matrix (illustrating element labels). Note that the first three atoms within the Zmatrix do not use the full number of parameters; only at the fourth atom are there enough previously-defined atoms for all of the parameters to be specified. Here is another Z-matrix form for this same molecule: 0 C1 C2 H3 H4 H5 H6 H7 H8

1

C1 RCC C1 RCH C1 RCH C1 RCH C2 RCH C2 RCH C2 RCH Variables: RCH = 1.5 RCC = 1.1 ACCH = 111.2

C2 C2 C2 C1 C1 C1

ACCH ACCH ACCH ACCH ACCH ACCH

H3 H3 H3 H6 H6

120. -120. 180. 120. -120.


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In this Z-matrix, the literal bond lengths and angle values have been replaced with variables. The values of the variables are given in a separate section following the specification of the final atom. Variable definitions are separated from the atom position definitions by a blank line or a line like the following: Variables:

Symmetry constraints on the molecule are reflected in the internal coordinates. The C-H bond distances are all specified by the same variable, as are the C-C bond distances and the C-C-H bond angles. This Z-matrix form may be used at any time, and it is required as the starting structure for a geometry optimization using internal coordinates (i.e., Opt=Z-matrix). In the latter case, the variables indicate the items to be optimized; see the examples for the Opt keyword for more details. Specifying Periodic Systems

Periodic systems are specified with a normal molecule specification for the unit cell. The only additional required input are one, two or three translation vectors appended to the molecule specification (with no intervening blank line), indicating the replication direction(s). For example, the following input specifies a one-dimensional PBC single point energy calculation for neoprene: # PBEPBE/6-31g(d,p)/Auto SCF=Tight neoprene, [-CH2-CH=C(Cl)-CH2-] optimized geometry 0 1 C,-1.9267226529,0.4060180273,0.0316702826 H,-2.3523143977,0.9206168644,0.9131400756 H,-1.8372739404,1.1548899113,-0.770750797 C,-0.5737182157,-0.1434584477,0.3762843235 H,-0.5015912465,-0.7653394047,1.2791284293 C,0.5790889876,0.0220081655,-0.3005160849 C,1.9237098673,-0.5258773194,0.0966261209 H,1.772234452,-1.2511397907,0.915962512 H,2.3627869487,-1.0792380182,-0.752511583 Cl,0.6209825739,0.9860944599,-1.7876398696 TV,4.8477468928,0.1714181332,0.5112729831

The final line specifies the translation vector. Note that it specifies TV as the atom symbol. The following molecule specification could be used for a two-dimensional PBC calculation on BN: 0,1 5 7

0 0

-0.635463 -0.635463

0.000000 0.000000


0.733871 -0.733871

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7 5 TV TV

0 0 0 0

0.635463 0.635463 0.000000 2.541855

0.000000 0.000000 0.000000 0.000000

1.467642 -1.467642 4.403026 0.000000

Here is the molecule specification for a graphite sheet: 0 1 C C TV TV

0.000000 0.000000 2.475315 -1.219952

0.000000 1.429118 0.000000 2.133447

0.000000 0.000000 0.000000 0.000000

Finally, here is the molecule specification that could be used for a three-dimensional PBC calculation on gallium arsenide: 0 1 Ga

0.000000

0.000000

0.000000

Ga Ga Ga As As As As TV TV TV

0.000000 2.825000 2.825000 1.412500 1.412500 4.237500 4.237500 5.650000 0.000000 0.000000

2.825000 0.000000 2.825000 1.412500 4.237500 1.412500 4.237500 0.000000 5.650000 0.000000

2.825000 2.825000 0.000000 1.412500 4.237500 4.237500 1.412500 0.000000 0.000000 5.650000

Specifying Isotopes and other Nuclear Parameters

Isotopes and other nuclear parameters can be specified within the atom type field using parenthesized keywords and values, as in the following example: C(Iso=13,Spin=3) 0.0 0.0 0.0

The line specifies a 13C atom with a nuclear spin of 3/2 (3 * 1/2), located at the origin. The following items may be included in the list of parameters: •

• •

• •

Iso=n: Isotope selection. If integers are used to specify the atomic masses, the program will automatically use the corresponding actual exact isotopic mass (e.g., 18 specifies 18O, and Gaussian uses the value 17.99916). Spin=n: Nuclear spin, in units of 1/2. ZEff=n: Effective charge. This parameter is used in spin orbit coupling (see CASSCF=SpinOrbit), and the ESR g tensor and the electronic spin-molecular rotation hyperfine tensor (NMR Output=Pickett ). QMom=n: Nuclear quadrupole moment. GFac=n: Nuclear g-factor.

Molecular Mechanics Atom Types


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Molecule specifications for molecular mechanics calculations may also include atom typing and partial charge information. Here are some examples: C-CT C-CT-0.32 O-O--0.5

Specifies an SP3 aliphatic carbon atom. Specifies an SP3 aliphatic carbon atom with a partial charge of 0.32. Specifies a carbonyl group oxygen atom with a partial charge of -0.5.

Atom types and optional partial charges can be specified for each atom. Nuclear parameters can also be defined, as in these examples: C-CT(Iso=13) C-CT--0.1(Spin=3)

Specifying Ghost Atoms

An atom with mechanics type Bq (e.g.., "O-Bq") is set up as a ghost [393] of the corresponding atom, with its normal basis functions and numerical integration grid points but no nuclear charge or electrons. This requests a counterpoise calculation. Such calculations differ slightly from ones requested with Massage in previous versions of Gaussian in that they include the grid points from the ghost atoms in DFT XC quadrature. The new way is a more consistent superposition correction and also easier to use. Note that counterpoise calculations can also be requested with the Counterpoise keyword.

Multiple Gaussian jobs may be combined within a single input file. The input for each successive job is separated from that of the preceding job step by a line of the form: --Link1--

Here is an example input file containing two job steps: %Chk=freq # HF/6-31G(d) Freq Frequencies at STP

Molecule specification --Link1-%Chk=freq %NoSave # HF/6-31G(d) Geom=Check Guess=Read Freq=(ReadFC,ReadIsotopes) Frequencies at 300 K

charge and spin 300.0 2.0

Isotope specifications


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This input file computes vibrational frequencies and performs thermochemical analysis at two different temperatures and pressures: first at 298.15 K and 1 atmosphere, and then again at 300 K and 2 atmospheres. Note that a blank line must precede the --Link1-- line.

Gaussian 03 Keywords Online Help TOC

References

# Archive CASSCF Charge CNDO

ADMP B3LYP CBS Keywords ChkBasis Complex

AM1 BD CBSExtrapolate CID Constants

CPHF

Density

DensityFit

Dreiding ExtendedHuckel Frozen Core Field Options Frequency G* Keywords GFInput GFPrint Hartree-Fock Huckel IOp IRC MaxDisk MINDO3 MP* Keywords Name Opt Output PM3 Polar Prop Pseudo ReArchive SAC-CI SCF SCRF Stable Symmetry Test TestMO UFF Units Link 0 Zindo Commands Obsolete Keywords

External

Amber BOMD CCD CIS Counterpoise Density Functional Methods ExtraBasis

FMM

Force

Gen Guess INDO IRCMax MM NMR OVGF Population Punch Scale SP TD TrackIO Volume Non-Standard Routes

Geom GVB Integral LSDA MNDO ONIOM PBC Pressure QCISD Scan Sparse Temperature Transformation W1U Program Development Keywords

#


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The route section of a Gaussian job is initiated by a pound sign (#) as the first non-blank character of a line. The remainder of the section is in free-field format. For most jobs, all of the information can be placed on this first line, but overflow to other lines (which may but need not begin with a # symbol) is permissible. The route section must be terminated by a blank line. If no keywords are present in the route section, the calculation defaults to HF/STO-3G SP. ALTERNATE FORMS #N

Normal print level; this is the default. #P

Additional output is generated. This includes messages at the beginning and end of each link assortedinformation machine-dependent information (including execution timing data), as well giving as covergence in the SCF. #T

Terse output: output is reduced to essential information and results.

ADMP

This keyword requests a classical trajectory calculation [177,178,179,180] using the Atom Centered Density Matrix Propagation molecular dynamics model [188,189,190]. This method provides equivalent functionality to Born-Oppenheimer molecular dynamics (see the BOMD keyword) at considerably reduced computational cost [188]. ADMP belongs to the extended Lagrangian approach to molecular dynamics using Gaussian basis function and propagating the density matrix. The best known method of this type is Car-Parrinello (CP) molecular dynamics [191], in which the Kohn-Sham molecular orbitals, ψi, are chosen as the dynamical variables to represent the electronic degrees of freedom in the system. CP calculations are usually carried out in a plane wave basis Gaussian orbitals are sometimes added as an adjunct Unlike(although plane wave CP, it is not necessary to use pseudopotentials on [394,395,396]). hydrogen or to use Deuterium rather than hydrogen in the dynamics. Fictitious masses for the electronic degrees of freedom are set automatically [188] and can be small enough that thermostats are not required for good energy conservation.


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ADMP can be performed with semi-empirical, HF, and pure and hybrid DFT models (see availability section below for more details). It can be applied to molecules, clusters and periodic systems. PBC calculations use only the Γ point (i.e., no K-integration). OPTIONAL INPUT

Although most jobs will not require it, ADMP calculations can accept some optional input: [ Initial velocity for atom 1: x y z Initial velocity for atom 2: x y z ... Initial velocity for atom N: x y z

Optional initial Cartesian velocities (ReadVelocity and ReadMWVelocity options)

...] [ Atom1, Atom2, E0 , Len, De , Be ...]

Entire section is repeated NTraj times Optional Morse params. for each diatomic product Terminate subsection with a blank line.

First, the initial velocity for each atom is read if the ReadVelocity or ReadMWVelocity option is included. Each initial velocity is specified as a Cartesian velocity in atomic units (Bohr/sec) or as a mass-weighed Cartesian velocity (in amu1/2*Bohr/sec), respectively. One complete set of velocities is read for each requested trajectory computation. Morse parameter data may also be specified for each diatomic product. The Morse parameter data is used to determine the vibrational excitation of diatomic fragments using the EBK quantization rules. It consists of the atomic symbols for the two atoms, the bond length between them ( Len, in Angstroms), the energy at that distance ( E 0 in Hartrees), and the Morse curve parameters De (Hartrees) and Be (Angstroms-1). This input subsection is terminated by a blank line.

MaxPoints= n

Specifies the maximum number of steps that may be taken in each trajectory (the default is 50). If a trajectory job is restarted, the maximum number of steps will default to the number specified in the original calculation. Lowdin

Use the Löwdin basis for the orthonormal set. The other alternative is Choleski, which uses the Cholesky basis and is the default. NKE= N

Set the initial nuclear kinetic energy to N microHartrees. NuclearKineticEnergy is a synonym for this option.


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DKE= N

Set the initial density kinetic energy to N microHartrees. DensityKineticEnergy is a synonym for this option. ElectronMass= N

Set the fictitious mass to |N is /10000| amu (the default is N If =1000, in a fictitious mass ofelectron 0.1 amu). EMass a synonym for this option. N <0, resulting then uniform scaling is used for all basis functions. By default, core functions are weighted more heavily than valence functions. FullSCF

Do the dynamics with converged SCF results at each point. ReadVelocity

Read initial Cartesian velocities from the input stream. Note that the velocities must have the same symmetry orientation as the molecule. This option suppresses the fifth-order anharmonicity correction. ReadMWVelocity

Read initial mass-weighted Cartesian velocities from the input stream. Note that the velocities must have the same symmetry orientation as the molecule. This option suppresses the fifth-order anharmonicity correction. StepSize=n

Sets the step size in dynamics to n*0.0001 femtoseconds. BandGap

Whether diagonalize. the Fock matrix in order to report the band gap at each step. The default istoNoBandGap Restart

Restart an ADMP calculation from the checkpoint file. Note that options set in the original job will continue to be in effect and cannot be modified. You may also specify alternative isotopes for ADMP jobs using the standard method.

Semi-empirical, HF and DFT methods. The Int=AM1, Int=MNDO or Int=PM3 keyword is required for ADMP jobs using semi-empirical methods. If you require a spin-unrestricted wavefunction, include the UHF keyword as well.


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BOMD

The following sample ADMP input file will calculate a trajectory for H2CO dissociating to H2 + CO, starting at the transition state: # B3LYP/6-31G(d) ADMP Geom=Crowd Dissociation of H2CO --> H2 + CO 0 C O H H

1 1 r1 1 r2 2 a 1 r3 3 b 2 180.

r1 1.15275608 r2 1.74415774 r3 1.09413376 a 114.81897892 b 49.08562961

Final blank line

At the beginning of an ADMP calculation, the parameters used for the job are displayed in the output: TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ ------------------------------------------------------------------INPUT DATA FOR L121 General parameters: Maximum Steps = 50 Random Number Generator Seed = 398465 Time Step = 0.10000 femptosec Ficticious electronic mass = 0.10000 amu MW individual basis funct. = True Initial nuclear kin. energy = 0.10000 hartree Initial electr. kin. energy = 0.00000 hartree Initial electr. KE scheme = 0 Multitime step - NDtrC = 1 Multitime step - NDtrP = 1 No Thermostats chosen to control nuclear temperature Integration parameters: Follow Rxn Path (DVV) Constraint Scheme Projection of angular mom. Rotate density with nuclei

= False = 12 = True = True

The molecular coordinates and velocities appear at the beginning of each trajectory step (some output digits are truncated here to save space): Cartesian coordinates:


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I= 1 X= -1.1971360D-01 Y= 0.0000000D+00 Z= -1.0478570D+00 I= 2 X= -1.1971360D-01 Y= 0.0000000D+00 Z= 1.1305362D+00 I= 3 X= 2.8718451D+00 Y= 0.0000000D+00 Z= -2.4313539D+00 I= 4 X= 4.5350603D-01 Y= 0.0000000D+00 Z= -3.0344227D+00 MW Cartesian velocity: I= 1 X= -4.0368385D+12 Y= 1.4729976D+13 Z= 1.4109897D+14 I= 2 X= 4.4547606D+13 Y= -6.3068948D+12 Z= -2.2951936D+14 I= 3 X= -3.0488505D+13 Y= 6.0922004D+12 Z= 1.8527270D+14 I= 4 X= -1.3305097D+14 Y= -3.1794401D+13 Z= 2.4220839D+14 TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ

After the trajectory computation is complete, summary information is displayed in the output for each time step in the trajectory: Trajectory summary for trajectory Energy/gradient evaluations Hessian evaluations

1 51 51

Trajectory summary Time (fs) 0.000000 0.100000 0.200000 0.300000 ...

Kinetic (au) 0.1000000 0.0995307 0.0983706 0.0970481

Potent (au) -113.0500312 -113.0495469 -113.0483488 -113.0469941

Delta E (au) 0.0000000 0.0000150 0.0000531 0.0000852

Delta A (h-bar) 0.0000000000000000 0.0000000000000003 0.0000000000000009 0.0000000000000021

You can also use GaussView 3.0 or other visualization software to display the trajectory path in three dimensions.

AM1 This method keyword requests a semi-empirical calculation using the AM1 Hamiltonian [43,48,49,53,54,397,398,399,400,401,402]. No basis set keyword should be specified.

Energies, "analytic" gradients, and numerical frequencies.

The AM1 energy appears in the output file as follows (followed by the x, y, and z components of the dipole moment): Energy= -.091965532835 NIter= 10. Dipole moment= .000000 .000000 -.739540


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The energy is as defined by the AM1 model. Note that energy differences computed from the values in semi-empirical calculations are in Hartrees and may be compared directly with energy differences computed from jobs using other methods.

Molecular Mechanics Methods There are three molecular mechanics methods available in Gaussian. They were implemented for use in ONIOM calculations, but they are also available as independent methods. No basis set keyword should be specified with these keywords. The following force fields are available: AMBER : The AMBER force field as described in publication [37]. The actual ( parm96.dat ) have been updated slightly since the of thisparameters paper. We use this

current version from the AMBER web site (amber.scripps.edu). DREIDING: The DREIDING force field as described in [38]. UFF: The UFF force field as described in [39].

CHARGE ASSIGNMENT-RELATED OPTIONS

Unless set in the molecule specification input, no charges are assigned to atoms by default using molecular forcealgorithm field. Options available to estimatewhen charges at any the initial pointmechanics using the QEq underare control of the following options for any of the mechanics keywords: QEq

Assign charges to all atoms using the QEq method [40]. UnTyped

Assign QEq charges only to those atoms for which the user did not specify a particular type in the input. UnCharged

Assign QEq charges for all atoms which have charge zero (i.e., all atoms which were untyped or which were given a type but not a charge in the input). PARAMETER PRECEDENCE OPTIONS

Terminology: Gaussian contains built-in parameter sets for the built-in force fields listed above; these are referred to as hard-wired parameters. Soft parameters are ones specified


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by the user in the input stream for the current job (or a previous job when reading parameters from the checkpoint file). By default, when no relevant option is given, the hard-wired parameters are the only ones used. HardFirst

Read additional input stream, with hard-wired parameters having priority over theparameters read-in, softfrom ones.theHence, read-in parameters are used only if there is no corresponding hard-wired value. Note that wildcards matches within the hardwared parameter set take precidence over soft parameters, even when the latter contains an exact match for the same item. Use SoftFirst if you want to override hard-wired parameter matches. SoftFirst

Read additional parameters from the input stream, with soft (read-in) parameters having priority over the hard-wired values. SoftOnly

Read parameters from the input stream and use only them, ignoring hard-wired parameters. ChkParameters

Read parameters from the checkpoint file. Any non-standard (soft) parameters present in the checkpoint file are used with higher priority than corresponding hard-wired parameters, unless HardFirst is also specified. NewParameters

Ignore any parameters in the checkpoint file. Modify

Read modifications and additions to the parameter set (after it has been constructed from hard and/or soft parameters). HANDLING MULTIPLE PARAMETER SPECIFICATION MATCHES

Since parameters can be specified using wildcards, it is possible for more than one parameter specification to match a given structure. The default is to abort if there are any ambiguities in the force field. The following options specify other ways of dealing with multiple matches. FirstEquiv

If there are equivalent matches for a required parameter, use the first one

found. LastEquiv

If there are equivalent matches for a required parameter, use the last one found. INPUT CONVENTIONS


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AMBER calculations require that all atom types be explicitly specified using the usual notation within the normal molecule specification section: C-CT C-CT-0.32

Specifies an SP3 aliphatic carbon atom. Specifies an SP3 aliphatic carbon atom with a partial charge of 0.32.

O-O--0.5

Specifies a carbonyl group oxygen atom with a partial charge of -0.5.

Consult the AMBER paper [37] for definitions of atom types and their associated keywords. Atom types and charges may also be provided for UFF and DREIDING calculations, but they are not required. For these methods, the program will attempt to determine atom types automatically.

Analytic energies, gradients, and frequencies.

ONIOM, Geom=Connect

GENERAL MOLECULAR MECHANICS FORCE FIELD SPECIFICATIONS

Unless otherwise indicated, distances are in Angstroms, angles are in degrees, energies are in Kcal/mol and charges are in atomic units. Function equivalencies to those found in standard force fields are indicated in parentheses. In equations, R refers to distances and θ refers to angles. Wildcards may be used in any function definition. They are indicated by a 0 or an asterisk. In MM force fields, the non-bonded (Vanderwaals and electrostatic) interactions are evaluated for every possible pair of atoms. However, interactions between pairs of atoms that are separated by three bonds or less are usually scaled down (in most force fields, using a factor 0.0 for pairs separated by one or two bonds, and some value between 0.0 and 1.0 for pairs that are separated by three bonds). There are a number of ways to implement the calculation of non-bonded interactions. We follow a two-step procedure. First, we calculate the interactions between all pairs, without taking the scaling into account. In this step, we can use computationally efficient (linear scaling) algorithms. In the second step, we subtract out the contributions that


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should have been scaled, but were included in the first step. Since this involves only pairs that are close to each other based on the connectivity, the computer time for this step scales again linearly with the size of the system. Although at first sight it seems that too much work is done, the overall algorithm is the more efficient than the alternatives. In softand force input,entry the NBDir entry corresponds to the of all thethe pairs, thefield NBTerm is usedfunction for the subsequent subtraction ofcalculation the individual pairs. However, to make things easier, you can specify just the non-bonded master function NonBon, which is automatically expanded into the actual functions NBDir and NBTerm during pre-processing. Vanderwaals parameters, used for NBDir and NBTerm (See MMFF94 below for MMFF94-type Vanderwaals parameters). VDW Bond-length Well-depth

MMFF94 type Vanderwaals parameters (used for NBDir and NBTerm). VDW94 Atomic-pol NE Scale1 Scale2 DFlag

Atomic-pol Atomic polarizability (Angstrom3). NE Slater-Kirkwood effective number of valence electrons (dimensionless). Scale1 Scale factor (Angstrom1/4). Scale2 Scale factor (dimensionless). DFlag 1.0 for donor type atom, 2.0 for acceptor type, otherwise 0.0.

MMFF94 electrostatic buffering Buf94 Atom-type Value

Non-bonded interaction master function. This function will be expanded into pairs and a direct function ( NBDir and NBTerm) before evaluation of the MM energy. NonBon V-Type C-Type, V-Cutoff C-Cutoff VScale1 VScale2 VScale3 CScale1 CScale2

CScale3 V-Type is the Vanderwaals type:

0 1 2 3 4

No Vanderwaals Arithmetic (as for Dreiding) Geometric (as for UFF) Arithmetic (as for Amber) MMFF94-type Vanderwaals


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C-Type is the Coulomb type:

0 1 2 3

No Coulomb 1/R 1/R 2 1/R buffered (MMFF94)

V-Cutoff and C-Cutoff are the Vanderwaals and Coulomb cutoffs (respectively): 0 No cutoff

>0 <0

Hard cutoff Soft cutoff

VScale1-3 are Vanderwaals scale factors for 1 to 3 bond separated pairs. CScale1-3 are

Coulomb scale factors for 1 to 3 bond separated pairs. If any scale factor < 0.0, the 1/1.2 scaling is used (as for Amber). Coulomb and Vanderwaals direct (evaluated for all atom pairs). NBDir V-Type C-Type V-Cutoff C-Cutoff

V-Type, C-Type, V-Cutoff , and C-Cutoff as above.

Coulomb and Vanderwaals single term cutoffs NBTerm Atom-type1 Atom-type2 V-Type C-Type V-Cutoff C-Cutoff V-Scale C-Scale

V-Type, C-Type, V-Cutoff , C-Cutoff , V-Scale, and C-Scale as above.

Atomic single bond radius AtRad Atom-type Radius

Effective charge (UFF) EffChg Charge

GMP Electronegativity (UFF) EleNeg Value

Step down table


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Table Original-atom-type Stepping-down-type(s).

Harmonic stretch I (Amber [1]): ForceC *(R- Req)2 HrmStr1 Atom-type1 Atom-type2 ForceC Req

ForceC Force constant Req Equilibrium bond length

Harmonic stretch II (Dreiding [4a]): ForceC *[R-(R i+R j- Delta)]2 HrmStr2 Atom-type1 Atom-type2 ForceC Delta

ForceC Force constant Delta Delta Ri and R j are atomic bond radii specified with AtRad.

Harmonic stretch III (UFF [1a]): k *(R-R ij)2 Equilibrium bond length R ij = (1 - PropC *ln BO)*(R i + R j) + R en Force constant: k = 664.12*Zi*Z j/(R ij3) Electronegativity correction: R i*R j*[Sqrt(Xi) - Sqrt(X j)]2/(Xi*R i + X j*R j) HrmStr3 Atom-type1 Atom-type2 BO PropC

BO Bond order (if <0, it is determined on-the-fly) PropC Proportionality constant Ri and R j are atomic bond radii defined with AtRad. X i and X j are GMP electronegativity values defined with EleNeg. Z i and Z j are the effective atomic charges defined with EffChg.

Morse stretch I (Amber): DLim*(e-a(R-Req)-1)2 where a = Sqrt( ForceC / DLim) MrsStr1 Atom-type1 Atom-type2 ForceC Req DLim

ForceC Force constant Req Equilibrium bond length DLim Dissociation limit


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Morse stretch II (Dreiding [5a]): DLim*exp[-a(R i+R j- Delta)]-1)2 where a = Sqrt( ForceC / DLim) MrsStr2 Atom-type1 Atom-type2 ForceC Delta DLim

ForceC Force constant Delta Delta DLim Dissociation limit Ri and R j are atomic bond radii defined with AtRad.

Morse stretch III (UFF [1b]): A1* A3*(exp[-a(R-R ij)]-1)2 where a = Sqrt(k /[ BO* PropC ]) Equilibrium bond length R ij = (1 - PropC *ln BO)*(R i + R j) + R en Force constant k = 664.12*Zi*Z j/R ij3 Electronegativity correction: R en = R i*R j*(Sqrt(Xi) - Sqrt(X j))2/(Xi*R i + X j*R j) MrsStr3 Atom-type1 Atom-type2 BO PropC


Quartic stretch I (MMFF94 [2]): ( Req/2)*(R- ForceC )2*[1+CStr *(R- ForceC +(7/12)*CStr 2*(R- ForceC )2] QStr1 Atom-type1 Atom-type2 ForceC Req CStr

ForceC Force constant (md-Angstrom-1) Req Equilibrium bond length (Angstrom) CStr Cubic stretch constant (Angstrom-1)

Atomic torsional barrier for the oxygen column (UFF [16]) UFFVOx Barrier

Atomic sp3 torsional barrier (UFF [16]) UFFVsp3 Barrier


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Harmonic bend (Amber [1]): ForceC *(T-θeq)2 HrmBnd1 Atom-type1 Atom-type2 Atom-type3 ForceC θeq

ForceC Force constant (in kcal/(mol*rad2) θeq Equilibrium angle

Harmonic Bend (Dreiding [10a]): [ ForceC /sin( θeq2)]*(cos(θ)-cos(θeq))2 HrmBnd2 Atom-type1 Atom-type2 Atom-type3 ForceC θeq

ForceC Force constant θeq Equilibrium angle

Dreiding Linear Bend (Dreiding [10c]): AForceC *(1+cos(θ)) LinBnd1 Atom-type1 Atom-type2 Atom-type3 ForceC

ForceC Force constant

UFF 3-term bend (UFF [11]): k*(C0 + C1*cos(θ))+C2*cos(2θ) where C2=1/(4 * sin(θeq2)), C1 = -4*C2*cos(θeq) and C0=C2*(2*cos(θeq2)+1) Force constant: k = 664.12*Zi*Zk *(3*R ij*R jk *(1-cos(θeq2))-cos(θeq)*R ik 2)/R ik 5 UFFBnd3 Atom-type1 Atom-type2 Atom-type3 θeq BO12 BO23 PropC

θeq Equilibrium angle BO12 Bond order for Atom-type1–Atom-type2 (when <0, it is determined on-the-fly) BO23 Bond order for Atom-type2–Atom-type3 (when <0, it is determined on-the-fly) PropC Proportionality constant Ri, R j and Rk are atomic bond radii defined with AtRad. X i, X j and X k are GMP electronegativity defined with EleNeg. Z i, Z j and Z k are effective atomic charges defined

with EffChg.


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UFF 2-term bend (UFF [10]): [k/( Per 2)]*[1-cos( Per *θ)] 2 2 5 Force constant: k = 664.12*Zi*Zk *(3*R j*R i jk *(1-cos( Per ))-cos( Per )*R ik )/R ik

UFFBnd2 Atom-type1 Atom-type2 Atom-type3 Per BO12 BO23 PropC

Per Periodicity: 2 for linear, 3 for trigonal, 4 for square-planar. BO12 Bond order for Atom-type1–Atom-type2 (when <0, it is determined on-the-fly) BO23 Bond order for Atom-type2–Atom-type3 (when <0, it is determined on-the-fly) PropC Proportionality constant Ri, R j and Rk are atomic bond radii defined with AtRad. X i, X j and X k are GMP electronegativity defined with EleNeg. Z i, Z j and Z k are effective atomic charges defined

with EffChg. Zero bend term: used in rare cases where a bend is zero. This term is needed for the program not to protest about undefined angles. ZeroBnd Atom-type1 Atom-type2 Atom-type3

Cubic bend I (MMFF94 [3]): ( ForceC /2)*(1+CBend *(θ-θeq))*(θ-θeq)2 CubBnd1 Atom-type1 Atom-type2 Atom-type3 ForceC θeq CBend

ForceC Force constant (in md*Angstrom/rad2) θeq Equilibrium angle CBend "Cubic Bend" constant (in deg-1)

MMFF94 Linear Bend (MMFF94 [4]): ForceC *(1+cos(θ)) LinBnd2 Atom-type1 Atom-type2 Atom-type3 ForceC

ForceC Force constant (md)

Amber torsion (Amber [1]): Σi=1,4 (Mag i*[1+cos(i*θ-I(i+4))])/ NPaths AmbTrs Atom-type1 A-type2 A-type3 A-type4 PO1 PO2 PO3 PO4 Mag 1 Mag 2 Mag 3

Mag 4 NPaths


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PO1-PO4 Phase offsets Mag 1...Mag 4 V/2 magnitudes NPaths Number of paths (if < 0, determined on-the-fly).

Dreiding torsion (Dreiding [13]): V *[1-cos( Period *(θ- PO))]/(2* NPaths) DreiTrs Atom-type1 Atom-type2 Atom-type3 Atom-type4 V PO Period NPaths V Barrier height V PO Phase offset Period Periodicity NPaths Number of paths (if < 0, determined on-the-fly).

UFF torsion with constant barrier height (UFF [15]): [V /2]*[1cos( Period * PO)*cos(V *θ)]/ NPaths UFFTorC Atom-type1 Atom-type2 Atom-type3 Atom-type4 Period PO V NPaths

Period Periodicity PO Phase offset V Barrier height V NPaths Number of paths. When zero or less, determined on-the-fly.

UFF torsion with bond order based barrier height (UFF [17]): [V/2]*[1-cos( Period * PO)* cos( Period *θ)]/ NPaths where V = 5*Sqrt(U j*Uk )*[1+4.18*Log( BO12)] UFFTorB Atom-type1 Atom-type2 Atom-type3 Atom-type4 Period PO BO12 NPaths

Period Periodicity PO Phase offset BO12 Bond order for Atom-type1–Atom-type2 (when <0, it is determined on-the-fly) NPaths Number of paths (when <0, it is determined on-the-fly) U j and U k are atomic constants defined with UFFVsp2.

UFF torsion with atom type-based barrier height (UFF [16]): [V/2]*[1-cos( Period * PO)* cos( Period *θ)]/ NPaths where V=Sqrt(V j*Vk ) UFFTor1 Atom-type1 Atom-type2 Atom-type3 Atom-type4 Period PO NPaths


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Period Periodicity PO Phase offset NPaths Number of paths. When zero or less, determined on-the-fly. V j and V k are atomic constants defined with UFFVsp3.

UFF torsion with atom type based barrier height (UFF [16]) (differs from UFFTor1 in that the atomic parameter that is used): [V/2]*[1cos( Period * PO)*cos( Period *θ)]/ NPAths where V=Sqrt(V j*Vk ) UFFTor2 Atom-type1 Atom-type2 Atom-type3 Atom-type4 Period PO NPaths

Period Periodicity PO Phase offset NPaths Number of paths. When zero or less, determined on-the-fly. V j and V k are atomic constants from UFFVOx.

Dreiding special torsion for compatibility with Gaussian 98 code. During processing, it is replaced with DreiTRS, with the following parameters: •

•

•

If there are three atoms bonded to the third center and the fourth center is H, it is removed. If there are three atoms bonded to the third center, and at least one of them is H, but the fourth center is not H, then these values are used: V =4.0, PO=0.0, Period =3.0, and NPaths=-1.0. Otherwise, these values are used: V =1.0, PO=0.0, Period =6.0, and NPaths=-1.0.

OldTor Atom-type1 Atom-type2 Atom-type3 Atom-type4

Improper torsion (Amber [1]): Mag *[1+cos( Period *(θ- PO))] ImpTrs Atom-type1 Atom-type2 Atom-type3 Atom-type4 Mag PO Period

Mag V/2 Magnitude PO Phase offset Period Periodicity

Three term Wilson angle (Dreiding [28c], UFF [19]): ForceC *(C1 + C2*cos(θ) + C3*cos(2θ)) averaged over all three Wilson angles θ. Wilson Atom-type1 Atom-type2 Atom-type3 Atom-type4 ForceC C1 C2 C3


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ForceC Force constant C1, C2, C3 Coefficients

Harmonic Wilson angle (MMFF94 [6]): ( ForceC /2)*(θ2) summed over all three Wilson angles θ. HrmWil Atom-type1 Atom-type2 Atom-type3 Atom-type4 ForceC


Stretch-bend I (MMFF94 [5]): ( ForceC1*(R 12- Req12)+ ForceC2*(R 32- Req23))*(θ-θeq) StrBnd1 Atom-type1 Atom-type2 Atom-type3 ForceC1 ForceC2 Req 12 Req23 θeq

ForceC1, ForceC2 Force constants (in md/rad) Req12, Req23 Equilibrium bond lengths θeq Equilibrium angle USING SUBSTRUCTURES

Substructures may be used to define different parameter values for a function for distinct ranges of some geometrical characteristic. Substructure numbers are appended to the function name, separated by a hyphen (e.g., HrmStr-1, HrmStr-2 and so on). The following substructures apply to functions related to bond stretches: • • •

-1 -2 -3

Single bond: 0.00 ≤ bond order < 1.50 Double bond: 1.50 ≤bond order < 2.50 Triple bond: bond order ≥ 2.50

The following substructures apply to functions for bond angles (values in degrees): First substructure : • • •

-1 -2 -3

0 ≤ θ ≤ 45 45 < θ ≤ 135 135 < θ ≤ 180

Second substructure: •

-i-n

Number of atoms bonded to the central one.

For dihedral angles, one or two substructures may be used (e.g., AmbTrs-1-2). Use a zero for the first substructure to specify only the second substructure.


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First substructure : • • • •

-0 -1 -2

Skip this substructure (substructure "wildcard") Single central bond: 0.00 ≤ bond order < 1.50 Double central bond: 1.50 ≤ bond order < 2.50

Triple central bond: bond order ≥ 2.50 Second substructure: • • •

-3

-i-1 -i-2 -i-3

Resonance central bond (1.30 ≤ bond order ≤ 1.70) Amide central bond (priority over resonance) None of the above

Here is some simple MM force field definition input: HrmStr1 HrmStr1-1 HrmStr1-2 HrmBnd2 DreiTrs-1 DreiTrs-2

H_ C_2 C_2 * * *

C_2 360.0 1.08 C_2 350.0 1.50 C_2 500.0 1.40 C_2 * 50.0 120.0 C_2 C_2 * 5.0 180.0 C_2 C_2 * 45.0 180.0

2.0 -1.0 2.0 -1.0

Archive This keyword directs Gaussian to place the results from the calculation into the site archive (job results database) if the job completes successfully. The GAUSS_ARCHDIR environment variable specifies the location of the archive files. The Test keyword may be used to suppress automatic archiving. In this case, archive entries are still listed at the end of the output file (from which they may be extracted at a later time if desired). NoTest is a synonym for Archive. Not all job types may be archived. See the discussion of the individual keywords for such limitations. Archiving is also disabled by default whenever the IOp keyword is used to set internal program options; the Archive keyword can override this.

Rearchive, Test


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Here is a sample archive entry, as it appears at the conclusion of a Gaussian 03 output file: 1\1\GINC-JANIS\SP\RHF\STO-3G\H2O1\MJFRISCH\24-Oct-2004\0\\#T TEST POP=NONE\\Water single point energy\\0,1\O\H,1,1.\H,1,1.,2,120.\\V ersion=IBM-RS6000-G03RevA.1\HF=-74.9490523\RMSD=5.447e-04\PG=C02V [C2(O1),SGV (H2)]\\@

The lines of the archive entry are wrapped without regard to word breaks. Fields within the archive entry are separated by backslashes, sections are separated by multiple backslashes, and the entry ends with an at sign (@). The archive entry records the site, user, date, and program version used for the calculation, as well as the route section and the title section for the job. It also contains the molecule specification or optimized geometry and all of the calculation's essential results. Note, however, that it does not include quantities which can be rapidly recomputed from them (such as thermochemistry results for a frequency calculation). For those job types which cannot be archived, the following line will appear in the output file in place of the archive entry: This type of calculation cannot be archived.

B3LYP See DFT Methods below.

BD This method keyword requests a Brueckner Doubles calculation [73,74].

T

Requests a Brueckner Doubles calculation with a triples contribution [73] added. BD-T is a synonym for BD(T). TQ

Requests a Brueckner Doubles calculation with triples and quadruples contributions [64] added.


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FC

This indicates "frozen-core," and it implies that inner-shells are excluded from the correlation calculation. This is the default calculation mode. See FC for full information. MaxCyc=n

Specifies the maximum number of cycles.

Analytic energies, numerical gradients, and numerical frequencies.

The BD energy appears in the output labeled E(CORR), following the final correlation iteration: DE(CORR)=

-.55299518D-01

E(CORR)=

-.75019628089D+02

The energy is given in Hartrees. If triples (or triples and quadruples) were requested, the energy including these corrections appears after the above: Brueckner Doubles with Triples and Quadruples (BD(TQ)) ======================================================== Saving the triples amplitudes on disk, using 192 words of disk. T4(aaa)= .00000000D+00 T4(aab)= -.40349028D-04 T4(abb)= -.40349028D-04 T4(bbb)= .00000000D+00 Time for triples= .10 seconds. Disk space used for TT scratch files : 512 words E5TTaaa = .00000000D+00E5TTaab = -.12350750D-04 E5TTabb = -.12350750D-04 E5TTbbb = .00000000D+00 E5TT = -.24701500D-04 E5TQ2 = .68473650D-05 EQQ2 = -.44495423D-04 DE5 = -.62349557751D-04 BD(TQ) = -.75019771137D+02

The section gives information about the computation of the non-iterative triples and quadruples correction. The final energy appears in the last line, labeled BD(TQ).

BOMD


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This keyword requests a classical trajectory calculation [177,178,179,180] using a BornOppenheimer molecular dynamics model (first described in [181,182]; see [403] for an extended review article). The implementation in Gaussian 03 [184,186,187] extends the usual methodology by using a very accurate Hessian based algorithm that incorporates a predictor step on the local quadratic surface followed by a corrector step. The latter uses a fifth-order polynomial or a rational fitted to thefor energy, gradient Hessianstep at the beginning and end points of eachfunction step. This method generating the and correction enables an increase in the step size of a factor of 10 or more over previous implementations. The selection of the initial conditions using quasi-classical fixed normal mode sampling and the final product analysis are carried out in the same manner as in the classical trajectory program VENUS [404]. Alternatively, initial Cartesian coordinates and velocities may be read in. Note that the ADMP method provides equivalent functionality at substantially lower computational cost at the Hartree-Fock and DFT levels. REQUIRED INPUT

All BOMD jobs must specify the number of dissociation paths; for many jobs, this value will be zero (a blank line is also allowed), and no other BOMD input will be used. In this case, the trajectory is integrated for a fixed number of steps, as specified by the program default of 100 or the value of the MaxPoints option. If NPath is set to -1, the dissociation pathways will be detected automatically and a gradient criteria (Hartree/Bohr) will be used in place of the usual fragmentation pathway and stopping criteria. When the number of dissociation paths is greater than zero, the full BOMD job input has the following general structure: NPath dissociation paths (maximum=20) IFrag1, ..., IFrag NAtoms information ... times [R1, R2, R3, R4, G5, ITest, IAtom, JAtom, R6 criteria (ReadStop option) ...] times [Estart,DelE,SBeta,Ef,DPert,IFlag ] simulated annealing params. (SimAnneal) [Mode-num, VibEng(Mode-num), ...] normal mode energies (NSample) [Initial velocity for atom 1: x y z velocities


Number of Fragmentation Repeated NPath Optional stopping Repeated NPath Optional Optional initial Optional initial

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Initial velocity for atom 2: x y z or ReadMWVelocity) ... Initial velocity for atom N: x y z ...] repeated NTraj times [Atom1, Atom2, E 0, Len, D e, Be params. for each diatomic product ...]

(ReadVelocity

Entire section is Optional Morse

Terminate subsection with a blank line.

The input line(s) following NPath define the fragmentation information for each path. The value in each position specifies that the corresponding atom belongs to the specified fragment number (i.e., atom i belongs to fragment number IFrag i). Note that fragment information for each path must begin on a new line, but the ones for any individual path may be continued over as many lines as necessary. ReadStop option is specified. Up to six Stopping criteria may are specified nextfor when stopping criteria be specified eachthe path. A trajectory is terminated when all of the active criteria are satisfied. However, a value of zero for any parameter turns off testing for the corresponding stopping criteria. The stopping criteria tests are defined as follows (default parameter values are in parentheses): •

• •

• • • •

Minimum distance between the centers of mass for any pair of fragments > R1 (18) Minimum distance between atoms located in different fragments > R2 (20) Maximum distance between the center of mass and any atom in the same fragment < R3 (0) The maximumgradient distance R6 (0) Otherwise, distance between atoms IAtom and JAtom < R6 (0)

All distances are specified in Bohr, and the units of the gradient G5 are Hartrees/Bohr. Parameters for simulated annealing/fragmentation follow the stopping criteria in the input stream when the SimAnneal option is specified: • • • •

• •

Estart is the desired initial kinetic energy (Hartrees). DelE gain/loss in Hartrees. SBetaisisthe theenergy Fermi-Dirac inverse temperature (1/Hartrees). Ef is the Fermi energy (wavenumbers): all modes corresponding to a frequency in wavenumbers below Ef will be enhanced, whole those above Ef will be reduced. The reverse will happen if SBeta is negative. DPert is the size of the random perturbation. IFlag determines the algorithm for applying an energy perturbation for simulated

annealing (i.e., adding/removing energy from the eigenmodes). It has the


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following possible values: 0 (weigh each eigencomponent according to its frequency), 1 (add DelE in a random fashion), 2 (combination of 0 and 1), 00 (if near a transition state, add all energy along that mode), and 10 (ignore any nearby transition state). The next part of the inputFor specifies how much energy in each normal modeinwhen the in NSample option is used. each mode, VibEng is theistranslational energy kcal/mol the forward direction along the transition vector. If VibEng < 0, then the initial velocity is in the reverse direction. (You can explicitly specify the forward direction using the Phase option.) Next, the initial velocity for each atom is read if the ReadVelocity or ReadMWVelocity option is included. Each initial velocity is specified as a Cartesian velocity in atomic units (Bohr/sec) or as a mass-weighed Cartesian velocity (in amu1/2*Bohr/sec), respectively. One complete set of velocities is read for each requested trajectory computation. Finally, Morse parameter data can bethespecified for each diatomic product.fragments The Morseusing parameter data is used to determine vibrational excitation of diatomic the EBK quantization rules. It consists of the atomic symbols for the two atoms, the bond length between them ( Len, in Angstroms), the energy at that distance ( E 0 in Hartrees), and the Morse curve parameters De (Hartrees) and Be (Angstroms-1). This input subsection is terminated by a blank line.

MaxPoints= n

Specifies the maximum number of steps that may be taken in each trajectory (the default is 100). If a trajectory job is restarted, the maximum number of steps will default to the number specified in the original calculation. Phase=( N1,N2 [ ,N3[, N4]])

Defines the phase for the transition vector such that forward motion along the transition vector corresponds to an increase in the specified internal coordinate. If two atom numbers are given, the coordinate is a bond stretch between the two atoms; three atom numbers specify an angle bend and four atoms define a dihedral angle. ReadVelocity

Read initial Cartesian velocities from the input stream. Note that the velocities must have the same symmetry orientation as the molecule. This option suppresses the fifth-order anharmonicity correction. ReadMWVelocity

Read initial mass-weighted Cartesian velocities from the input stream. Note that the velocities must have the same symmetry orientation as the molecule. This option suppresses the fifth-order anharmonicity correction.


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SimAnneal

Use simulated annealing (the initial velocity is randomly generated). Additional parameters are read in, as described above. Only one of ReadVelocity, ReadMWVelocity and SimAnneal can be specified. ReadStop

Read in alternative stopping criteria. RTemp= N

Specifies the rotational temperature. The default is to choose the initial rotational energy from a thermal distribution assuming a symmetric top (the temperature defaults to 0 K). NSample= N

Read in initial kinetic energies for the first N normal modes (the default is 0). The energies for the remaining modes are determined by thermal sampling by default. NTraj= N

Compute N trajectories. Update=n

By default BOMD does second derivatives at every point. Using the Update keyword causes the program to perform Hessians update for n gradient points before doing a new analytic Hessian. GradOnly requests that only gradients be done and that the Hessian be updated all the time (full second derivatives are not computed). StepSize=n

Sets the step size in dynamics to n*0.0001 femtoseconds. Sample=type

Specifies the type of sampling, where type is one of these keywords: Orthant, Microcanonical , Fixed, and Local. The default is Fixed normal mode energy unless RTemp was specified, in which case Local mode sampling is implied. Restart

Restart a trajectory calculation from the checkpoint file. Note that options set in the original job will continue to be in effect and cannot be modified. You may also specify alternative isotopes for BOMD jobs using the standard method.

All semi-empirical, SCF, CASSCF, CIS, MP2 and DFT methods.


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ADMP

The following sample BOMD input file illustrates many of the available options. It will calculate a trajectory for H2CO dissociating to H2 + CO, starting at the transition state. There is one fragmentation pathway: C and O belong to fragment 1, and the two hydrogens belong to fragment 2. Stopping criteria are also specified in this example job. The trajectory will be stopped if the distance between the centers of mass of H2 and CO exceed 13 bohr, the closest distance between H2 and CO exceeds 11 bohr, all atoms in a fragment are less than 1.3 bohr from the center of mass of the fragment, any atom in the fragment is less than 2.5 bohr from all other atoms in the fragment, the gradient for the separation of the fragments is less than 0.0000005 hartree/bohr, and the distance between atoms 1 and 3 is greater than 12.8 bohr. The initial kinetic energy along the transition vector is 5.145 kcal/mol, in the direction of the products (the forward direction is characterized by an increase in the larger C-H distance). The Morse parameters for H2 and CO are specified to determine the vibrational excitation of the product diatomics; they were computed in a previous calculation. The calculation will be carried out at 300 K. # HF/3-21G BOMD(Phase=(1,3),RTemp=300,NSample=1,ReadStop Geom=Crowd HF/3-21G dissociation of H2CO --> H2 + CO 0 C O H H

1 1 r1 1 r2 2 a 1 r3 3 b 2 180.

r1 1.15275608 r2 1.74415774 r3 1.09413376 a 114.81897892 b 49.08562961 1 1 1 2 2 13.0 11.0 1.3 2.5 0.0000005 1 1 3 12.8 1 5.145 C O -112.09329898 1.12895435 0.49458169 2.24078955 H H -1.12295984 0.73482237 0.19500473 1.94603924

Final blank line

Note that all six stopping criteria are used here only for illustrative purposes. In most cases, one or two stopping criteria are sufficient.


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At the beginning of a BOMD calculation, the parameters used for the job are displayed in the output: TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ-TRJ ------------------------------------------------------------------INPUT DATA FOR L118 ------------------------------------------------------------------General parameters: Max. points for each Traj. = 100 Total Number of Trajectories = 1 Random Number Generator Seed = 398465 Trajectory Step Size = 0.250 sqrt(amu)*bohr Sampling parameters: Vib Energy Sampling Option Vib Sampling Temperature Sampling direction Rot Energy Sampling Option

= Thermal sampling = 300.0 K = Forward = Thermal distribution (symmetric top)

Rot point Sampling Temperature = Start scaling criteria = ...

300.0 K 1.000D-05 Hartree

Reaction Path 1 **************** Fragment 1 center 1 ( C ) 2 ( O ) Fragment 2 center 3 ( H ) 4 ( H ) Termination criteria: The CM distances are larger than 13.000 bohr The min atomic distances among fragments are larger than 11.0 bohr The max atomic and CM distances in frags are shorter than 1.3 bohr The max atomic distances in fragments are short than 2.500 bohr The change of gradient along CM is less than 5.00D-07 Hartree/bohr Distance between atom center 1 ( C ) and 3 ( H ) is GE 12.800 bohr Morse parameters for diatomic fragments: E0 Re De Be C O -112.0932990 1.1289544 0.4945817 2.2407896 H H -1.1229598 0.7348224 0.1950047 1.9460392 ---------------------------------------------------------------------

The initial kinetic energies for the normal modes appears at the beginning of each trajectory step: ------------------------------------------------------Thermal Sampling of Vibrational Modes Mode Wavenumber Vib. quant.# Energy (kcal/mol) ------------------------------------------------------1 -2212.761 5.14500 2 837.330 0 1.19702 3 1113.182 0 1.59137 4 1392.476 0 1.99064 5 2026.859 0 2.89754 6 3168.689 0 4.52987


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-------------------------------------------------------

After the trajectory computation is complete, summary information is displayed in the output: Trajectory summary for trajectory Energy/gradient evaluations Hessian evaluations Trajectory Time (fs) 0.000000 1.169296 2.161873 ...

summary Kinetic (au) Potent (au) 0.0214192 -113.0388912 0.0293490 -113.0468302 0.0407383 -113.0582248

1 76 76

Delta E (au) Delta A (h-bar) 0.0000000 0.0000000000000000 -0.0000091 0.0000000000053006 -0.0000144 0.0000000000045404

The information is given for each time step in the trajectory. In addition, the output includes geometrical parameters for the atoms in each fragment, the distances between fragments, the relative mass-weighted velocities each fragments3.0and fragments, and all reported at each time step. You can alsoforuse GaussView or between other visualization software to display the trajectory path in three dimensions.

CASSCF

This method keyword requests a Complete Active Space Multiconfiguration SCF (MCSCF) [97,98,137,138,195,405]. An MC-SCF is a combination an SCF computation with a full CI involving a subset calculation of the orbitals; this subset is of known as the active space. The number of electrons ( N ) and the number of orbitals (M ) in the active space for a CASSCF must be specified following the keyword: CASSCF( N ,M ). Note that options may be interspersed with N and M in any order. By default, the active space is defined assuming that the electrons come from the highest occupied orbitals in the initial guess determinant and that the remaining orbitals required for the active space come from the lowest virtuals of the initial guess. Thus, for a 4electron, 6-orbital CAS-specified as CASSCF(4,6)-on a closed-shell system, the active space would consist of: •

•

Enough occupied orbitals from the guess to provide 4 electrons. Thus, the 2 highest occupied MOs would be included. Enough virtual orbitals to make a total of 6 orbitals. Since 2 occupied orbitals were included, the lowest 4 virtual orbitals would become part of the active space.


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Similarly, a 4 electron, 6 orbital CAS on a triplet would include the highest 3 occupied orbitals (one of which is doubly occupied and two singly occupied in the guess determinant) and the lowest 3 virtual orbitals. In Gaussian 03, algorithmic improvements make an active space of up to about 14 orbitals feasible [99,100,102]. Above 8 orbitals, the CASSCF code automatically uses this new direct method for matrix elements. Normally, Guess=Alter or Guess=Permute is necessary to ensure that the orbitals which are selected involve the electrons of interest and that they are correlated correctly. A prior run with Guess=Only can be used to quickly determine the orbital symmetries (see the first example below). Alternatively, a full Hartree-Fock single point calculation may be done, and the subsequent job will include Guess=(Read,Permute) in order to retrieve and then modify the computed initial guess from the checkpoint file. You need to include Pop=Regular in the route section of the preliminary job in order to include the orbital coefficient information in the output (use Pop=Full for cases where you need to examine more than just the few lowest virtual orbitals). Alternatively, you may use Pop=NBOSave to save the NBOs, which are often the best choice for starting CAS orbitals. You3.0. may also choose to view the orbitals in a visualization package such as GaussView By default, CASSCF calculations use a direct algorithm to avoid disk storage of integrals. A conventional algorithm may be selected by including SCF=Conven in the route section. CAS is a synonym for CASSCF.

Use #P in the route section to include the final eigenvalues and eigenvectors in addition to the energy and one-electron density matrix in the CASSCF output. A brief overview of the CASSCF method is given in chapter 9 (exercises 5 and 6) and appendix A of Exploring Chemistry with Electronic Structure Methods , 2nd ed. [308]. See reference [138] for a detailed discussion on the choice of an active space. See this page for a discussion of efficiency considerations for CASSCF calculations. Note: CASSCF is a powerful but advanced method with many subtleties. We strongly

recommend that you study the cited references before attempting to run production CASSCF calculations (this is especially true for CASSCF MP2). Example applications are discussed in references [406,407,408,409,410,411,412]. VARIATIONS •

•

An MP2-level electron correlation correction to the CASSCF energy may be computed during a CASSCF calculation by specifying the MP2 keyword in addition to CASSCF within the route section [101]. Calculations on excited states of molecular systems may be requested using the NRoot option. Note that a value of 1 specifies the ground state, not the first excited state (in contrast to usage with the CIS keyword).


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•

•

•

•

• •

State-averaged CASSCF calculations may be performed using the StateAverage and NRoot options to specify the states to be used. Conical intersections and avoided crossings may be computed by including Opt=Conical in the route section of a CASSCF job (see the examples) [165,166,167]. Approximate spin orbitbycoupling between two spinoption states can be computed during CASSCF calculations including the SpinOrbit [250,251,252,253,254,413,414]. The method used in Gaussian 03 is based on reference [254]. It is available for the elements H through Cl. In order to compute the spin orbit coupling, the integrals are computed in a oneelectron approximation involving relativistic terms, and then effective charges are used that scale the Z value for each atom to empirically account for 2 electron effects. This value can be specified for each atom via the molecule specification nuclear parameters list. Finally, note that such calculations will be state-averaged by default. The Restricted Active Space variation (RASSCF) [103] is now supported [104]. It RAS option. is selected thesections: RASSCF partitionoccupied the molecular orbitals intoviafive the lowest lyingcalculations occupieds (doubly in all configurations), the RAS1 space of doubly occupied MOs, the RAS2 space containing the most important orbitals for the problem, the RAS3 space of weakly occupied MOs and the remaining unoccupied orbitals. Thus, the active space in CASSCF calculations is divided into three parts in a RAS calculations, and allowed configurations are defined by specifying the minimum number of electrons that must be present in the RAS1 space and the maximum number that may be in the RAS3 space, in addition to the total number of electrons in the three RAS spaces. See the discussion of the RAS option for the methods for specifying these values.

NRoot= j

Requests that the jth root of the CI be used, so that an excited state is obtained when j > 1. The option defaults to the ground state ( j=1). The state specified by NRoot is referred to as the "state of interest." StateAverage

Used to specify a state-averaged CASSCF calculation. All states up to NRoot are averaged. This option requires the weighting for the various states to be input in format nF10.8 (no trailing blank line). StateAverage is not allowed in combination with Opt=Conical or CASSCF=SpinOrbit, both of which perform state-averaged calculations by default. SpinOrbit

Compute approximate spin orbit coupling between two states, specified on a separate input line. Implies a state-averaged CASSCF calculation.


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RAS=(a,b,c,d )

Requests a RASSCF calculation which allows up to a holes (i.e., excitations from RAS1 into RAS2 or RAS3) in the b orbitals in the RAS1 space, and to c particles in the d orbitals in the RAS3 space (i.e., excitations from RAS1 or RAS2 into RAS3). Thus, the minimum number of electrons in RAS2 is 2b-a. Note that the two CASSCF keyword parameters examples). specify the size of the entire active space: RAS1 + RAS2 + RAS3 (see the DavidsonDiag

Requests the use of the Davidson diagonalization method for the CI matrix instead of the Lanczos iterations. Lanczos is the default for NRoot values of 1 or 2; otherwise, Davidson is the default. FullDiag

Requests the use of the full (Jacobi) diagonalization method for the CI matrix instead of Lanczos or Davidson iterations. The default is full diagonalization if there are 6 or fewer active orbitals. NoFullDiag suppresses the use of the full diagonalization method. The full Jacobi diagonalization method must be used if quadratic convergence is required (see the QC option below), and when one knows nothing at all about the CI eigenvector (in the latter case, specify FullDiag for calculations involving more than 6 active orbitals) StateGuess=k

Set the starting vector for the Lanczos method to configuration k . For example, this option can be useful for selecting a configuration of the correct symmetry for a desired excited state (different from that of the ground state). In such cases, running a preliminary calculation to determine the orbital symmetries may be required. k may also be set to the special value Read, which says to read in the entire eigenvector from the input stream (format: NZ , ( Ind(I ), C(Ind(I )), I=1, NZ ).

The default diagonalization method is most efficient if the size of the CI problem is greater than about 50, or the user can identify one or more dominant components in the eigenvector from the onset of the calculation, via the initial trail vector. By default, the starting vector is initialized in j+1 positions, where j is the value given to the NRoot option (or its default value). The positions correspond to the lowest j+1 energy diagonal elements of the CI Hamiltonian. This usually results in good convergence for the lowest j roots. The StateGuess option (below) may be used to change this default. CASSCF(…,StateGuess= k ) sets C(k ) to 1.0. The central requirement for this vector is that it not be deficient in the eigenvector that is required. Thus, if the CI eigenvector is dominated by configuration k, setting the StateGuess option to k will generate a good starting vector (e.g., StateGuess=1 is appropriate if the CI vector is dominated by the SCF wavefunction). However, if the coefficient of configuration k is exactly zero (e.g.,


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by symmetry) in the desired root, then that eigenvector will be missing, and the calculation will converge to a higher state. OrbRot OrbRot includes and NoCPMCSCF excludes the orbital rotation derivative

contributions the default. from the CP-MC-SCF equations in an Opt=Conical calculation. OrbRot is SlaterDet

Use Slater determinants in the CASSCF calculation. This option is needed to locate a conical intersection/avoided crossing between a singlet state and a triplet state. HWDet

Use Hartree-Waller determinants instead of Slater. This is the default for CAS calculations involving 10 or more orbitals. It implies NoFullDiag. RFO

Requests the RFO quadratic step. At most, one of QC and RFO should be specified. QC

Requests a quadratically convergent algorithm for the CAS. This option should be used with caution; it works well only with a very good guess. Only one of QC and RFO should be specified. UNO

Requests that the initial orbitals for the CAS be produced from the natural orbitals generated from a previous UHF calculation [415,416]. Normally used with Guess=Read. The UNO guess must be used with caution. Often, some of the natural orbitals which have modest occupation are not the important ones for the process of interest. Consequently, unless the entire valence space is being correlated (which is usually prohibitively expensive), one normally runs one job which does a UHF calculation with Pop=NaturalOrbital , and then examines the resulting orbitals. The orbitals which belong in the active space are then selected, and a single-point CASSCF(…,UNO) Guess=(Read, Alter) calculation is performed. The resulting converged orbitals are then examined to verify that the correct active space has been located, and finally an optimization can be run with CASSCF(…,UNO) Guess=Read. For singlets, this entire process depends on the user being able to coax the UHF wavefunction to converge to the appropriate broken spin-symmetry (non-RHF) result. NPairs=n Number of GVB pairs outside of the CAS active space in a CAS-GVB calculation [417].


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Energies, analytic gradients, and analytic and numerical frequencies. CASSCF may not be combined with any semi-empirical method. Analytic polarizabilities may not be performed with the CASSCF method. Use CASSCF Polar=Numer. You can restart a CASSCF calculation by specifying SCF=Restart in the route section. In order to restart a CASSCF optimization, the keywords CASSCF Opt=Restart Extralinks=L405 must be included in the job's route section.

Opt=Conical, MP2, Guess, Pop, SCF

We will consider several of the most important uses of the CASSCF method in this section. Preliminary Examination of the Orbitals (Guess=Only). The following route section

illustrates one method of quickly examining the orbitals in order to determine their symmetries and any alterations needed to produce the desired initial state. We include Pop=Reg to obtain the molecular orbital output in the population analysis section: # HF/3-21G Guess=Only Pop=Reg Test

2h The molecule being investigated is 1,3-cyclobutadiene, with Dspace: symmetry. We are going to run a 4x4 CAS, so there will be four orbitalsa singlet in the active 2 occupied and 2 virtual. We want all four orbitals to be π orbitals.

The HOMO is orbital 14; therefore, orbitals 13 through 16 will comprise the active space. When we examine these orbitals, we see that only orbitals 14 and 15 are of the correct type. The molecule lies in the YZ-plane, so π orbitals will have significantly non-zero coefficients in the X direction. Here are the relevant coefficients for orbitals 10 and 1316: Molecular Orbital Coefficients 10 13 O O 3 1 C 2PX 0.29536 0.00000 7 3PX 0.16911 0.00000 12 2 C 2PX 0.29536 0.00000 16 3PX 0.16911 0.00000 21 3 C 2PX 0.29536 0.00000 25 3PX 0.16911 0.00000 30 4 C 2PX 0.29536 0.00000 34 3PX 0.16911 0.00000


14 O 0.34716 0.21750 0.34716 0.21750 -0.34716 -0.21750 -0.34716 -0.21750

15 V 0.37752 0.24339 -0.37752 -0.24339 -0.37752 -0.24339 0.37752 0.24339

16 V 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000

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Orbital 10 is clearly also a π orbital. If we look at higher virtual orbitals, we will find that orbital 19 is also a π orbital. We have found our four necessary orbitals, and can now use Guess=Alter to move them into the active space. Here is the input file for the CASSCF calculation: # CASSCF(4,4)/3-21G Guess=Alter Pop=Reg

Test

1,3-Cyclobutadiene Singlet, D2H, Pi 4x4 CAS 0 1

molecule specification 10,13 16,19

Interchange orbitals 10 and 13 . Interchange orbitals 16 and 19.

CASSCF Energy and the One-Electron Density Matrix . When we run this CASSCF

calculation on cyclobutadiene, we will obtain a prediction for the energy. It appears in the CASSCF output as follows: TOTAL -152.836259 ... energy at each iteration ITN= 9 MaxIt= 64 E= -152.8402786733 DE=-1.17D-05 Acc= 1.00D-05 ITN= 10 MaxIt= 64 E= -152.8402826495 DE=-3.98D-06 Acc= 1.00D-05 ... DO AN EXTRA-ITERATION FOR FINAL PRINTING

The value of E for the final iteration is the predicted energy: -152.8402826495 hartrees in this case. It is also important to examine the one-electron density matrix, which appears next in the output: Final one electron 1 1 0.191842D+01 2 -0.139172D-05 3 0.345450D-05 4 0.327584D-06 MCSCF converged.

symbolic density matrix: 2 3 0.182680D+01 0.130613D-05 0.415187D-05

0.172679D+00 0.564187D-06

4

0.820965D-01

The diagonal elements indicate the approximate occupancies for each successive orbital in the activethe space. If any ofsimilarly, these values is (essentially) zero, then2,that was empty throughout calculation; if any of them is essentially thenorbital that orbital was doubly occupied throughout the CAS. In either case, there were no excitations into or out of the orbital in question, and there is probably a problem with the CASSCF calculation. In our case, the two "occupied" orbitals have values less than 2, and the other two orbitals in the active space have non-zero occupancies, so things are fine.


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CASSCF MP2 Energy. When you run a CASSCF calculation with correlation (CASSCF MP2 in the route section), the following additional lines will appear in the

CASSCF output (with the first one coming significantly before the second): MP2 correction to the MCSCF energy is computed Indicates a CASSCF MP2 job. ... E2 = -0.2635549296D+00 EUMP2 = -0.15310383973610D+03

Electron correlation-corrected energy.

The string EUMP2 labels the energy; in this case, the value is -153.1038397361 hartrees. CAS Configuration Information. The beginning of the CASSCF

output lists the

configurations, in the following format: PRIMARY BASIS FUNCTION= 1 2 2 1 1 3 2 1

1

2 SYMMETRY TYPE = 0

3 2 SYMMETRY TYPE = 0 3 2

The first line indicates the electron assignments for the reference configuration. This is a 4x4 CAS, so the primary basis function output indicates that there is an α and b electron in both orbitals 13 and 14 (the numbers refer to the orbitals in the active space, from lowest to highest, and the electron order in the output is: α α β β). In configuration 2, the α electron in orbital 13 remains there, the α electron from orbital 14 has been excited to orbital 15, the β electron in orbital 13 remains there, as does the β electron in orbital 14. Similarly, in configuration 3, there is a β electron in orbital 13, an α (from 13) and β electron in orbital 14, and an α electron in orbital 15. The following two-step job illustrates one method for studying excited state systems using the CASSCF method. The first step assumes that a preliminary Hartree-Fock single point calculation has been done in order to examine the orbitals; it takes advantage of the initial guess computation done by that job, which it retrieves from the checkpoint file: Using CASSCF to Study Excited States.

%chk=CAS1 # CASSCF(2,4) 6-31+G(D) Guess=(Read,Alter) Pop=NaturalOrbital Test Geom=Check Alter the guess so that the three LUMOs are all the desired symmetry, and run the CAS 0,1 orbital alterations


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--Link1-%chk=CAS1 %nosave # CASSCF(2,4,NRoot=2) 6-31+G(D) Guess(Read) Pop(NaturalOrbital) Geom=Check Test Excited state calculation 0,1

The second job step uses the NRoot option to CASSCF to specify the first excited state. The first excitation energy for the system will then be computed by taking the energy difference between the two states (see exercise 5 in chapter 9 of Exploring Chemistry with Electronic Structure Methods [308] for a more detailed discussion of this technique). Predicting Conical Intersections. Including Opt=Conical keyword in the route section

changes the job from an optimization of the specified state using CASSCF to a search for a conical intersection or avoided crossing involving that state. The optimized structure will be that of the conical intersection or avoided crossing. Distinguishing between these two possibilities may be accomplished by examining the final eigenvalues in the CASSCF output for the final optimization step (it precedes the optimized structure): FINAL EIGENVALUES AND EIGENVECTORS VECTOR EIGENVALUES CORRESPONDING EIGENVECTOR state

energy

1

-154.0503161

2

-154.0501151

0.72053292 -0.16028934E-02 0.45467877

-0.48879229 ... 0.31874441E-02 ... 0.77417416 ...

If the two eigenvalues (thethe first entry inofthe labelled a stateand number) essentially the same, then energies thelines two states arewith the same, it is a are conical intersection. Otherwise, it is an avoided crossing. Spin Orbit Coupling. Here is the output from a CASSCF calculation where the spin orbit coupling has been requested with the Spin option (the coupling is between the state specified to the NRoot option and the next lower state): **************************** spin-orbit coupling program **************************** Number of configs= 4 1st state is 1 Identifies the two states between which the spin orbit coupling is computed. 2nd state is 2 Transition Spin Density Matrix 1 2 1 .000000D+00 .141313D+01 2 .553225D-01 .000000D+00 magnitude in x-direction= .0000000 cm-1 magnitude in y-direction= .0000000 cm-1


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magnitude in z-direction= 55.2016070 cm-1 total magnitude= 55.2016070 cm-1 MCSCF converged.

Spin orbit coupling.

The spin orbit coupling is broken down into X, Y, and Z components, followed by its total magnitude, which in this case is 55.2016070 cm-1. RASSCF example. Here is an example RASSCF calculation route section: # CAS(16,18,RASSCF(1,2,3,4)) 6-31G(d)

If this molecule is a neutral singlet, then this route defines the following spaces: RAS1 with 2 orbitals, 3 or 4 electrons in all configurations; RAS2 with 12 orbitals, 12 electrons in the reference configuration; and RAS3 with 4 orbitals, 0-3 electrons in all configurations. Thus, the RAS2 space will have 9 to 13 electrons in all configurations. The orbitals taken from the reference determinant for the active space are (assuming a spin singlet) the 8 highest occupieds and 10 lowest virtuals: i.e., same orbitals as for a regular CAS(16,18).

CBS-4M CBS-Lq CBS-Q CBS-QB3 CBS-APNO These method keywords specify the various Complete Basis Set (CBS) methods of Petersson and coworkers for computing very accurate energies {Nyden, 1981 #301; Petersson, 1988 #338; Petersson, 1991 #302; Petersson, 1991 #303; Montgomery Jr., 1994 #304; Ochterski, 1996 #307; Montgomery Jr, 1999 #503; Montgomery Jr., 2000 #794}. The keywords refer to the modified version of CBS-4 {Ochterski, 1996 #307; Montgomery Jr., 2000 #794}, CBS-q {Petersson, 1991 #303} (i.e., Lq for "little q"), CBS-Q {Ochterski, 1996 #307}, CBS-Q//B3 {Montgomery Jr, 1999 #503; Montgomery Jr., 2000 #794} and CBS-APNO {Ochterski, 1996 #307} methods, respectively. No basis set should be specified with any of these keywords. These methods are complex energy computations involving several to many pre-defined calculations on the specified system. All of these distinct steps are performed automatically when one of these keywords is specified, and the final computed energy value is displayed in the output.


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Either of the Opt=Maxcyc=n or QCISD=Maxcyc=n keywords may be used in conjunction with any of the these keywords to specify the maximum number of optimization or QCISD cycles, respectively. You should specify alternative isotopes for CBS jobs using the standard method. However, the ReadIsotopes option is retained for rerunning completed calculations under different conditions (see the examples).

ReadIsotopes

Specify alternate temperature, pressure, and/or isotopes (the defaults are 298.15 K, 1 atmosphere, and the most abundant isotopes). This information appears in a separate input section having the format: temp pressure [ scale]

Values must be real numbers.

isotope mass for atom 1 isotope mass for atom 2 ... isotope mass for atom n

where temp, pressure, and scale are the desired temperature, pressure, and an optional scale factor for frequency data when used for thermochemical analysis (the default is the value defined by the selected method). The remaining lines hold the isotope masses for the various atoms in the molecule, arranged in the same order as they appeared in the molecule specification section. If integers are used to specify the atomic masses, the program will automatically use the corresponding actual exact mass (e.g., 18 specifies O18, and Gaussian uses the value 17.99916). Restart

Restart from the checkpoint file from a previous CBS calculation. If the previous calculation did not complete, it will be completed.

Energies only. CBS-4M, CBS-Lq, CBS-Q and CBS-QB3 are available for first and second row atoms; CBS-APNO is available for first row atoms only. The CBS-4and model chemistry has also been updated with both Jr., the 2000 new localization procedure improved empirical parameters {Montgomery #794}. The new version, CBS-4M, (M referring to the use of Minimal Population localization) is recommended for new studies; the CBS-4O keyword requests the earlier parametrization.


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The output from each step of a CBS method calculation is included in the output file. The final section of the file contains a summary of the results of the entire run. CBS Summary Output. Here is the output from a CBS-Q calculation on CH2 (triplet

state): Complete Basis Set (CBS) Extrapolation: G. Petersson and M. A. Al-Laham, JCP 94, 6081 (1991) G. Petersson, T. Tensfeldt & J. A. Montgomery, JCP 94, 6091 (1991) additional references ... Temperature= E(ZPE)= E(SCF)= DE(CBS)= DE(QCI)= DE(Empirical)= CBS-Q (0 K)= CBS-Q Enthalpy=

298.150000 .016835 -38.936531 -.011929 -.002781 -.005891 -39.069447 -39.065647

Pressure= E(Thermal)= DE(MP2)= DE(MP34)= DE(Int)=

1.000000 .019690 -.114652 -.018702 .004204

CBS-Q Energy= -39.066592 CBS-Q Free Energy= -39.043444

The temperature and pressure are given first, followed by the components terms of the CBS-Q energy. The second-to-last line gives the CBS-Q energy values (reading across): at 0 K and at the specified temperature (298.15 K by default). The final line gives the CBS-Q enthalpy (including the thermal correction for the specified temperature) and the Gibbs free energy computed via the CBS-Q method (i.e., the CBS-Q energy including the frequency job free-energy correction). All of the energies are in hartrees. Rerunning the Calculation at a Different Temperature. The following two-step job

illustrates the method for running a second (very rapid) CBS calculation at a different temperature. This job computes the CBS-4 energy at 298.15 K and then again at 300 K: %Chk=cbs # CBS-4 Test CBS-4 on formaldehyde 0 1

molecule specification --Link1-%Chk=cbs %NoSave # CBS-4(Restart,ReadIso) Geom=AllCheck Test 300.0 1.0

isotope specifications

CBSExtrapolate


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This keyword requests a general Complete Basis Set extrapolation of the MP2 energy [87,88,89,327]. The method requires two parameters: the minimum number of pair natural orbitals and the integration grid. The first can be specified with the NMin option, and it defaults to 5 for the 6-31G**, 6-31G†† and 6-311G** basis sets (with or without diffuse functions), and to 10 for the 6-311G basis set with (2df,p) or (3df,p) polarization functions (again, or without diffuse functions). NMin must be specified in all other cases, or an error with will result. The default integration grid is the (99,590) grid; an alternate grid can be specified with the Int=Grid keyword. The integration portion is a small part of the total CBS extrapolation computation, so this relatively large grid was chosen. See the description of the Integral keyword for a full discussion of the available grids. REQUIRED OPTION NMin= N

Specifies N as the minimum number of pair natural orbitals. ADDITIONAL OPTIONS MinPopLocal

Use localization based on populations in minimal basis [92]. This is the default. PopLocal

Use population localization as described in reference [418]. BoysLocal

Use Boys localization [419,420,421]. NoLocal

Do not use any localization. NRPopLocal

Newton-Raphson population localization. NRBoysLocal

Newton-Raphson Boys localization. NRMinPopLocal

Use 2nd order minimal population analysis.

Single point energy calculations only, using any electron correlation method.


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Int=Grid, CBS keywords

CCD CCSD These method keywords request a coupled cluster [67,422] calculations, using double substitutions from the Hartree-Fock determinant for CCD [67], or both single and double substitutions for CCSD [68,69,70,71]. CC and QCID are synonyms for CCD.

FC

All frozen core options are available with CCD and CCSD. T

Include triple excitations non-iteratively [72] (CCSD only). CCSD-T is a synonym for CCSD(T). E4T

Used with the T option to request inclusion of triple excitations for both the complete MP4 and to form CCSD(T). T1Diag

Computes the T1 diagnostic of T. J. Lee and coworkers [423](CCSD only). Conver=N

Sets the convergence calculations to 10-N on the energy and 10-(N+2) on the wavefunction. The default is N =7 for single points and N =8 for gradients. MaxCyc=n

Specifies the maximum number of cycles for CCSD calculations.

Analytic energies and gradients for CCD and CCSD, numerical gradients for CCSD(T), and numerical frequencies for all methods.

MP4, Transformation, QCISD


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The Coupled Cluster energy appears in the output as follows (following the final correlation iteration): DE(CORR)= ...

CCSD(T)=

-.54979226D-01

E(CORR)=

-.75019641794D+02

-.75019717665D+02

The CCSD energy is labeled E(CORR), and the energy including the non-iterative triples contribution is given in the final line.

Charge

The Charge keyword requests that a background charge distribution be included in the calculation. The charge distribution is made up of point charges [424,425]. Only valid for single point calculations. By default, the charges are read from the input stream, one per line, in this format: x y z charge 0.0 A [ρ B]

where x,y,z are the coordinates in the input orientation (in the units specified by the Units keyword) and defaulting to Angstroms), charge is the charge, 0.0 is a fixed field, and the remaining items are parameters in the following equation for the additional electron repulsive term:

Angstroms

Indicates that input charge locations are specified in Angstroms. Bohrs

Indicates that input charge locations are specified in Bohrs.


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StandardOrientation

Indicates that the input charges are specified in the standard orientation rather than the input orientation. Use the %KJob=L301 Link 0 command to quickly determine the standard orientation for a molecule. Check

Reads the background charge distribution from the checkpoint file.

Single point energies, optimizations and frequencies. Not valid with semi-empirical methods or PBC.

%KJob, Units

To perform geometry optimizations in the presence of background charges, you must use Opt=Z-Matrix NoSymm keywords and define the input geometry either in traditional Zmatrix coordinates or symbolic Cartesian coordinates. Here is an example: # RHF/STO-3G Opt=Z-Matrix Charge NoSymm Water, STO-3G, point charges 0,1 O H 1 R1 H 1 R2 2 A1 Variables: R1=1.0 R2=1.0 A1=105. 2.0 2.0 2.0 1.2 2.0 -2.0 2.0 1.1

ChkBasis The ChkBasis keyword requests that the basis set be read from the checkpoint file, and is useful in compound jobs involving general basis sets by allowing them to have only one


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copy of the basis set in the input stream (see the discussion of the Gen keyword below). Note, however, that ChkBasis can be used to retrieve whatever basis set exists in a checkpoint file, regardless of how it was originally specified. ECP's specified in the basis set are also retrieved, as are the choices for pure vs. Cartesian functions. ChkBasis will also retrieve any density fitting basis in the checkpoint file. By Seedefault, the examples for other possibilities.

Of course, no basis set keyword should be specified with ChkBasis. CheckPointBasis , ReadBasis, and RdBasis are all synonyms for ChkBasis.

Gen, GenECP, Pseudo, ExtraBasis, ExtraDensityBasis

The following route section will retrieve the basis set and density fitting set (if any) from the checkpoint file and use them for the current job: # BLYP/ChkBasis

The following route section will retrieve only the basis set from the checkpoint file, and an automatically generated density fitting basis will be used: # BLYP/ChkBasis/Auto

The following route section will retrieve only the density fitting basis from the checkpoint file: # BLYP/6-31G(d)/ChkBasis

CID CISD

These method keywords request a Hartree-Fock calculation followed by configuration interaction with all double substitutions (CID) or all single and double substitutions (CISD) from the Hartree-Fock reference determinant [61,143,202]. CIDS and CI are synonyms for CISD.


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FC

All frozen core options are available with CID and CISD. Conver=N


Specifies the maximum number of cycles for CISD calculations.

Energies, analytic gradients, and numerical frequencies.

Transformation

The CI energy appears in the output as follows: DE(CI)= NORM(A) =

-.48299990D-01 .10129586D+01

E(CI)=

-.75009023292D+02

The output following the final CI iteration gives the predicted total energy. The second output line displays the value of Norm(A). Norm(A)-1 gives a measure of the correlation correction to the wavefunction; the coefficient of the HF configuration is thus 1/Norm(A). Note that the wavefunction is stored in intermediate normalization; that is:

where Ψ0 is the Hartree-Fock determinant and has a coefficient of 1 (which is what intermediate normalization means). Norm(A) is the factor by which to divide the wavefunction as given above to fully normalize it. Thus:


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The coefficient of the Hartree-Fock determinant in the fully normalized wavefunction is then 1/Norm(A), the coefficient of singly-excited determinantΨi→a is Tia/Norm(A), and so on.

CIS CIS(D)

The CIS method keyword requests a calculation on excited states using single-excitation CI (CI-Singles) [108]. Chapter 9 of Exploring Chemistry with Electronic Structure Methods [308] provides a detailed discussion of this method and its uses. The CIS(D) keyword and option is used to request the related CIS(D) method [426,427]. You can also follow a CIS job with a CIS(D) job to compute the excitation energies for additional states (see the examples). CIS jobs can include the Density keyword; without options, this keyword causes the population analysis to use the current (CIS) density rather than its default of the Hartree-

Fock density. Note that Density cannot be used with CIS(D). STATE SELECTION OPTIONS Singlets

Solve only for singlet excited states. This option only affects calculations on closed-shell systems, for which it is the default. Triplets

Solve only for triplet excited states. This option only affects calculations on closed-shell systems. 50-50

Solve for half triplet and half singlet states. This option only affects calculations on closed-shell systems. Root= N

Specifies the "state of interest" for which the generalized density is to be computed. The default is the first excited state ( N =1).


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NStates=M

Solve for M states (the default is 3). If 50-50 is requested, NStates gives the number of each type of state for which to solve (i.e., the default is 3 singlets and 3 triplets). Add= N

Read statesasoff theNStates checkpoint file be andused solve forthis an additional optionconverged implies Read well. cannot with option. N states. This DENSITY-RELATED OPTION AllTransitionDensities

Computes the transition densities between every pair of states. PROCEDURE- AND ALGORITHM-RELATED OPTIONS FC

All frozen core options are available with CIS and CIS(D). Direct

Forces solution of the CI-Singles equation using AO integrals which are recomputed as needed. CIS=Direct should be used only when the approximately 4O2 N2 words of disk required for the default (MO) algorithm are not available, or for larger calculations (over 200 basis functions). MO

Forces solution of the CI-Singles equations using transformed two-electron integrals. This is thekeyword, default algorithm in Gaussian 03.the Thedisk transformation attempts to honor the thus further moderating requirements. MaxDisk AO

Forces solution of the CI-Singles equations using the AO integrals, avoiding an integral transformation. The AO basis is seldom an optimal choice, except for small molecules on systems having very limited disk and memory. Conver= N

Sets the convergence calculations to 10-N on the energy and 10-(N+2) on the wavefunction. The default is N =4 for single points and N =6 for gradients. Read

Reads initial guesses for the CI-Singles states off the checkpoint file. Note that, unlike for SCF, an initial guess for one basis set cannot be used for a different one. Restart

Restarts the CI-Singles iterations off the checkpoint file. Also implies SCF=Restart.


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RWFRestart

Restarts the CI-Singles iterations off the read-write file. Useful when using non-standard routes to do successive CI-Singles calculations. EqSolv

Whether default. to perform equilibrium or non-equilibrium PCM solvation. NonEqSolv is the NoIVOGuess

Forces the use of canonical single excitations for the guess. IVOGuess, which uses improved virtual orbitals, is the default. DEBUGGING OPTIONS ICDiag

Forces in-core full diagonalization of the CI-Singles matrix formed in memory from transformed integrals. This is mainly a debugging option. MaxDiag= N

Limits the submatrix diagonalized in the Davidson procedure to dimension N . This is mainly a debugging option. MaxDavidson is a synonym for this option.

Energies, analytic gradients, and analytic frequencies for CIS, and energies for CIS(D).

ZINDO, TD, MaxDisk , Transformation, Density

CIS Output. There are no special features or pitfalls with CI-Singles input. Output from

a single point CI-Singles calculation resembles that of a ground-state CI or QCI run. An SCF is followed by the integral transformation and evaluation of the ground-state MP2 energy. Information about the iterative solution of the CI problem comes next; note that at the first iteration, additional initial guesses are made, to ensure that the requested number of excited states are found regardless of symmetry. After the first iteration, one new vector is added to the solution for each state on each iteration. The change in excitation energy and wavefunction for each state is printed for each iteration (in the #P output): Iteration 3 Dimension 27 Root 1 not converged, maximum delta is


0.002428737687607

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Root 2 not converged, maximum delta is 0.013107675296678 Root 3 not converged, maximum delta is 0.030654755631835 Excitation Energies [eV] at current iteration: Root 1 : 3.700631883679401 Change is -0.001084398684008 Root 2 : 7.841115226789293 Change is -0.011232152003400 Root 3 : 8.769540624626156 Change is -0.047396173133051

The iterative process can end successfully in two ways: generation of only vanishingly small expansion vectors, or negligible change in the updated wavefunction. When the CI has converged, the results are displayed, beginning with this banner: ***************************************************************** Excited States From singles matrix: *****************************************************************

The transition dipole moments between the ground and each excited state are then tabulated. Next, the results on each state are summarized, including the spin and spatial symmetry, the excitation energy, the oscillator strength, and the largest coefficients in theCI expansion (use IOp(9/40= N ) to request more coefficients: all that are greater than 10 N ): Excitation energies and oscillator strengths: symmetry excitation energy

oscillator strength Excited State f=0.0008 8 -> 9

1:

Singlet-A"

3.7006 eV

0.69112

335.03 nm

CI expansion coefficients for each

excitation. Excitation is from orbital 8 to orbital 9 This state for opt. and/or second-order corr.

interest.”

Total Energy, E(Cis)

=

=> This is the "state of

- 113.696894498

CIS energy

is repeated here for convenience.

For closed shell calculations, the sum of the squares of the expansion coefficients is normalized to total 1/2 (as the beta coefficients are not shown). For open shell calculations, the normalization sum is 1. Normalization.

Finding Additional States. The following route will read the CIS results from the

checkpoint file and solve for 6 additional states beyond the second state: # CIS=(D,Read,Root=2,NStates=6)

The same procedure will work using CIS(D) in the follow-up job.

CNDO


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This method keyword requests a semi-empirical calculation using the CNDO Hamiltonian [41]. No basis set keyword should be specified.


The CNDO energy appears in the output file as follows (followed by the x, y, and z components of the dipole moment): Energy=

-19.887711334547 NIter= 10.

Dipole moment=

.000000

.000000

-.739540

The energy is as defined by the CNDO model. Note that energy differences computed from the values in semi-empirical calculations are in Hartrees and may be compared directly with energy differences computed from jobs using other methods.

Complex

This keyword allows the molecular orbitals to become complex. It may only be used for closed-shell singlet states.

Analytic energies for Hartree-Fock and MP2 only, analytic HF gradients, and numerical HF frequencies.

SCF

Constants


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Specifies which set of physical constants to use. Note that using an older set should only be done in order to compare results with earlier versions of Gaussian.

1998

Constants from [428] and references therein. This is the default 1986

Constants used in Gaussian 88 through Gaussian 98, from [429,430]. 1979

Constants used in Gaussian 80 through Gaussian 86 , mostly from [431]. The OldConstants keyword is a synonym for Constants=1979 . CURRENT VALUES

Here are summarized various conversion factors and physical constants used by Gaussian 03 in converting from standard to atomic units. All quantities used in calculations inside Gaussian are in atomic units; the conversion factors are used only when processing input or generating printed output. Raw Constants. The constants which are stored directly in the program are:

1 Bohr (a0) = 0.5291772083 Å [428] 1 Atomic mass unit (amu) = 1.66053873 x 10-27 kilograms [428] 1 Electron charge (e) = 4.803242 x 10-10 ESU [432] = 1.602176462 x 10-19 Coulombs [428] Planck's constant (h) = 6.62606876 x 10-34 Joule-secs [428] Avogadro's number ( N A) = 6.02214199 x 1023 [428] 1 Calorie = 4.184 Joules [431] 1 Hartree = 4.3597482 x 10-18 Joules [429] Speed of light (c) = 2.99792458 x 1010 cm-sec-1 [431] Boltzman constant (k ) = 1.380603 x 10-23 Joules-degree-1 [428] Inverse fine structure constant (α-1) = 137.03599976 [428] Molar volume of ideal gas at 273.15 K = 0.022413996 m3 [428]


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Proton rest mass = 1.67262158 x 10-27 kg [428] Electron magnetic moment = 9.28476362 x 10-24 J-T-1 [428] Free electron g-factor = 2.002319304386 (dimensionless) [428] Conversion Factors. The following useful conversion factors can be derived from the

above: Electron mass = 0.910938 x 10-30 kg Proton mass = 1836.1527 electron mass 1 Atomic mass unit (amu) = 1822.8880 electron mass 1 Electron volt (eV) = 23.06055 kcal-mol-1 1 Hartree = 627.5095 kcal-mol-1 = 27.2114 eV 1 Bohr-electron = 2.541746 Debye = 2.541746 x 10 -18 esu-cm 1 Debye2-angstrom-2-amu-1 = 42.2561 km-mol-1 = 5.82573 x 10-3 cm-2-atm-1 at STP 1 Hartree-1/2-Bohr-1-amu-1/2 = 219474.6 cm-1 Electric field: 1 au = 5.142206 x 1011 V-m-1 -41

2-

2

-1

Electric polarizability: 1 au = 1.648777 x 10 C m -J Dipole moment = 1 Bohr-electron = 8.478352 x 10-30 C-m

Counterpoise Counterpoise corrections [433,434] may be computed using the Counterpoise keyword, which can be used on an energy calculation, optimization or frequency calculation or BOMD. Counterpoise keyword takes an integer value specifying the number of fragments or The monomers in the molecular structure. The facility also requires an additional integer to be placed at the end of each atom specification indicating which fragment/monomer it is part of.


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NewGhost

Requests new-style ghost atoms for which integration grid points for DFT quadrature are included. NewBq is a synonym for NewGhost. This is the default and the recommended method. OldGhost

Requests old-style ghost atoms. OldBq is a synonym for OldGhost. This option is only useful for comparison with previous results.

Counterpoise Input. Here are examples using a Z-matrix (left) and Cartesian

coordinates (right): # MP2/6-31G Counterpoise=2 Opt

# MP2/6-31G Counterpoise=2 Opt

Counterpoise with Z-matrix 0,1,0,3,1,2 O,0.0,0.0,0.0,1 structures begin here O,1,ROO,2 X,1,1.,2,X3O H,1,RO1H,3,HOX3,2,90.,0,1 H,1,RO1H,3,HOX3,2,-90.,0,1 X,2,1.,1,52.5,3,180.,0 H,2,RO2H1,6,H7OX,1,180.,0,2 H,2,RO2H2,6,H8OX,1,0.,0,2

Counterpoise with Cartesian 0,1 1 0.00 0.00 0.92 1 9 0.17 0.00 2.73 2 1 0.77 0.00 3.43 2 9 0.00 0.00 0.00 1

Z-matrix variables...

Note that the Z-matrix input requires a 0 after the dihedral angle value/variable (to indicate that the final angle is a dihedral) prior to the fragment number. Also, the first atom in the Z-matrix must be given in Cartesian coordinates. Clearly, using Cartesian coordinates for such jobs makes specifying fragment numbers in the input much more straightforward. The preceding Z-matrix also illustrates the use of fragment-specific charge and spin multiplicity specifications. The format of the corresponding input line in this case is: total-charge, total-spin, frag. 1-charge, frag.1 multiplicity, frag. 2 charge, frag. 2 multiplicity

An example counterpoise optimization using ECPs: # hf/lanl2dz counterpoise=2 nosymm opt test HBr + HF, optimization with counterpoise correction using ECP basis 0 1 H -0.046866

0.

0.586860

1


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Br F H

-0.331864 0.396755 0.584835

0. 0. 0.

-0.801000 2.739275 3.641534

1 2 2

Counterpoise Output. Here is some sample output from a Counterpoise

calculation:

Counterpoise: corrected energy = -2660.083831739527 Counterpoise: BSSE energy = 0.003902746890

These lines give the corrected energy and basis set superposition errors, respectively.

CPHF This keyword selects the algorithm used for solving the CPHF equations [435,436,437,438,439,440,441,442,443,444].

Grid= grid

Specify the integration grid for the CPHF portion of the calculation. The syntax is the same as for the Int=Grid option. The argument to this option may be a grid keyword (Fine, UltraFine, and so on) or a specific grid. See the discussion of Integral=Grid for full details on grid specification. The default to grid depends on the then one used for integral evaluation. any specific grid is specified theused Integral keyword, that grid is also used for the IfCPHF. Otherwise, when the latter uses the SG1 or Fine grid, the Coarse grid is used for the CPHF (a pruned (35,110)), and when UltraFine is used for the integrals, then SG1 is used for the CPHF. SG1 is the default grid for Polar=OptRot and Freq=Anharmonic. RdFreq

Perform frequency-dependent CPHF, reading in the frequencies for the electromagnetic field perturbation. The default is a static frequency calculation. This option causes the desired frequency to be read from the input stream. The default units for this value are Hartrees. Other units may be specified by including a suffix, one of cm (cm-1) and nm (wave numbers). This option is relevant for Freq and Polar jobs. EqSolv

Use equilibrium solvation. This is the default for static perturbations. NonEqSolv is the default for dynamic (non-zero frequency) perturbations.


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Simultaneous

Use one expansion space for all variables. This is faster than using separate spaces, but is slightly less accurate. This is the default. Separate

Use a separate).expansion space for each variable in the CPHF (the opposite of Simultaneous XY

Treat real and imaginary perturbations together. The opposite is NoXY, which does them separately. The default is to treat them separately if nuclear perturbations are also being done, but to treat them together if there are only electromagnetic perturbations. ZVector

Use the Z-Vector method [140,445,446] for post-SCF gradients. Allowed and the default if Hartree-Fock 2nd derivatives are not also requested. The NoZVector keyword says to use the full 3 x NAtoms CPHF for post-SCF gradients. AO

Solve CPHF in the atomic orbital basis [436,439,442,443]. This is the default. MO

Solve in the molecular orbital basis. MaxInv= N

Specifies the largest reduced space for in-core inversion during simultaneous solution (up to dimension N ). Larger reduced problems are solved by a second level of DIIS. The default is as large a space as memory permits. Conver= N

Set the CPHF convergence criterion to 10-N. The default is N =9 for CPHF=Separate and N =10 for CPHF=Simultaneous (the default). Canonical

Canonical CPHF, the default. MOD

Use MOD orbital derivatives for SAC-CI gradients (which uses configuration selection).

SCF

Density


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By default, population and other analysis procedures use the SCF density (i.e., the Hartree-Fock density for post-SCF methods; the DFT density for DFT jobs, and the CASSCF density for CAS jobs). The generalized densities for the MP2, MP3, MP4(SDQ), QCISD, CCD, CCSD, CID and CISD and SAC-CI methods are available. These are based on the Z-Vector [140,445,446,447], and hence yield multipole moments which are the correct analytical derivatives of the energy. The unrelaxed densities at second order (not the same as MP2) can also be used but are not recommended. The options of the Density keyword select which density to analyze. The Density keyword without an option is equivalent to Density=Current.

Current Use the density matrix for the current method. This is the default

when no option is given

to Density. All

Use all available densities. This is allowed for population analysis but not for electrostatics or density evaluation. Note that this option does not produce densities for all of the excited states in a CI-Singles calculation, only the density for the state of interest (see the examples below for a method of doing the former). SCF

Use the SCF density. HF is a synonym for SCF. MP2

Use the generalized density corresponding to the second-order energy. Transition= N or ( N ,M )

Use the CIS transition density between state M and state N . M defaults to 0, which corresponds to the ground state. AllTransition

Use all available CIS transition densities. CI

Use the generalized density corresponding to the CI energy. QCI

Use the generalized density corresponding to the QCI (or coupled cluster) energy. CC is a synonym for QCI.


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RhoCI

Use the one-particle density computed using the CI wavefunction for state N. This is not the same as the CI density [447], and its use is discouraged! Chapter 9 of Exploring Chemistry with Electronic Structure Methods discusses this issue [308]. Rho2

Use the density correct to second-order in Møller-Plesset theory. This is not the same as the MP2 density, and its use is discouraged! [447] CIS= N

Use the total unrelaxed CIS density for state N. Note that this is not the same as the density resulting from CIS(Root= N ,...) Density=Current , which is to be preferred [447]. Checkpoint

Recover the density from the checkpoint file for analysis. Implies Guess=Only ChkBasis: the calculation does not recompute new integrals, SCF, and so on, and retrieves the basis set from the checkpoint file.

Guess, ChkBasis

The following route section specifies a CI-Singles calculation which predicts the first six excited states of the molecule under investigation. The population and other analyses will use the CIS density corresponding to the lowest excited state: %Chk=benzene # CIS(NStates=6)/6-31+G(d,p) Density=Current Pop=CHelpG

The following route section may be used to rerun the post-CIS analyses for the other excited states: %Chk=benzene # CIS(Read,Root=N) Density=Current Pop=CHelpG # Guess=Read Geom=AllCheck

This route picks the converged and CIStowavefunction from thedensity checkpoint file, and performs theup necessary CPHF CIS calculation produce the relaxed for state N , which is then used in the population and other analyses.

DensityFit


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Controls density fitting for the Coulomb problem. Density fitting basis sets are specified as part of the model chemistry within the job's route section, discussed here. DenFit is a synonym for this keyword.

Iterative

Controls whether a generalized inverse is formed or the fitting equations are solved iteratively. NonIterative is the default except for ADMP. InvToler= N

Set the tolerance for a non-trivial eigenvalue of the generalized inverse of the fitting matrix to 10-N. Convergence= N

Specifies 10-N as the convergence criterion for iterative solution of the fitting equations. Implies Iterative. The default is 10-6 for ADMP and 10 –9 for the BOMD.

Applies only to DFT calculations using pure (non-hybrid) functionals.

ExtraDensityBasis , Gen, ChkBasis

Density Functional (DFT) Methods

Gaussian 03 offers a wide variety of Density Functional Theory (DFT) [75,76,448,449]

models (see also [448,450,451,452,453,454,455,456,457,458,459,460,461] for discussions of DFT methods and applications). Energies [78], analytic gradients, and true analytic frequencies [197,198,199] are available for all DFT models. The same optimum memory sizes given by freqmem are recommended for the more general models. The self-consistent reaction field (SCRF) can be used with DFT energies, optimizations, and frequency calculations to model systems in solution. Pure DFT calculations will often want to take advantage of density fitting. See the discussion here for details.


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The next subsection presents a very brief overview of the DFT approach. Following this, the specific functionals available in Gaussian 03 are given. The final subsection surveys considerations related to accuracy in DFT calculations. Note: Polarizability derivatives (Raman intensities) and hyperpolarizabilities are not

computed by default during DFT frequency calculations. Use Freq=Raman to request them. BACKGROUND

In Hartree-Fock theory, the energy has the form: EHF = V + + 1/2 - 1/2 where the terms have the following meanings: V The nuclear repulsion energy. P The density matrix. The one-electron (kinetic plus potential) energy 1/2 The classical coulomb repulsion of the electrons. -1/2 The exchange energy resulting from the quantum (fermion) nature of electrons. In density theory, the exchange (HF) forfunctional, a single determinant is replaced by a more functional general expression, theexact exchange-correlation which can include terms accounting for both exchange energy and the electron correlation which is omitted from Hartree-Fock theory: EKS = V + + 1/2 + EX[P] + EC[P] where EX[P] is the exchange functional, and EC[P] is the correlation functional. Hartree-Fock theory is really a special case of density functional theory, with EX[P] given by the exchange integral -1/2 and EC=0. The functionals normally used in density density functional gradient: theory are integrals of some function of the density and possibly the EX[P] = ∫f(ρα(r),ρβ(r), ∇ρα(r), ∇ρβ(r))dr where the methods differ in which function f is used for EX and which (if any) f is used for EC. In addition to pure DFT methods, Gaussian supports hybrid methods in which the exchange functional is a linear combination of the Hartree-Fock exchange and a


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functional integral of the above form. Proposed functionals lead to integrals which cannot be evaluated in closed form and are solved by numerical quadrature. KEYWORDS FOR DFT METHODS

Names forand thecorrelation various pure DFT models are given bystandard combining the names forinthe exchange functionals. In some cases, synonyms used the field are also available as keywords. Exchange Functionals. The following exchange functionals are available in Gaussian

03: •

•

•

•

•

•

•

•

Slater: ρ4/3 with theoretical coefficient of 2/3, also referred to as Local Spin Density exchange [75,76,77]. Keyword : Used Alone: HFS, Comb. Form: S Xαρ4/3 with the empirical coefficient of 0.7, usually used when this exchange functional is used without a correlation functional [75,76,77]. Keyword : Used XAlpha, Comb. Form: XA. Alone: Becke 88: Becke's 1988 functional, which includes the Slater exchange along with corrections involving the gradient of the density [462]. Keyword : Used Alone: HFB, Comb.Form: B. Perdew-Wang 91: The exchange component of Perdew and Wang's 1991 functional [463,464,465,466,467]. Keyword : Used Alone: N/A, Comb. Form: PW91. Barone's Modified PW91: The Perdew-Wang 1991 exchange functional as modified by Adamo and Barone [468]. Keyword : Used Alone: N/A, Comb. Form: MPW. Gill 96: The 1996 exchange functional of Gill [469,470]. Keyword : Used Alone: G96. N/A Form: PBE:, Comb. The 1996 functional of Perdew, Burke and Ernzerhof [471,472]. Keyword :

Used Alone: N/A, Comb. Form: PBE. OPTX: Handy's OPTX modification of Becke's exchange functional [474]. Keyword : Used Alone: N/A, Comb. Form: O.

The combination forms are used when one of these exchange functionals is used in combination with a correlation functional (see below). Correlation Functionals. The following correlation functionals are available, listed by

their corresponding keyword component: •

•

VWN: Vosko, Wilk, and Nusair 1980 correlation functional(III) fitting the RPA

solution to the uniform electron gas, often referred to as Local Spin Density (LSD) correlation [475] (functional III in the paper). VWN V(VWN5): Functional V from the 1980 paper which fits the Ceperly-Alder solution to the uniform electron gas (this is the functional recommended in the paper) [475].


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•

•

•

•

•

•

LYP: The correlation functional of Lee, Yang, and Parr which includes both local

and non-local terms [476,477]. PL (Perdew Local): The local (non-gradient corrected) functional of Perdew (1981) [478]. P86 (Perdew 86): The gradient corrections of Perdew, along with his 1981 local correlation functional [479]. 91): Perdew and Wang's 1991 gradient-corrected PW91 (Perdew/Wang correlation functional [463,464,465,466,467]. B95 (Becke 95): Becke's τ-dependent gradient-corrected correlation functional (defined as part of his one parameter hybrid functional [480]. PBE: The 1996 gradient-corrected correlation functional of Perdew, Burke and Ernzerhof [471,472].

All of the keywords for these correlation functionals must be combined with the keyword for the desired exchange functional. For example, BLYP requests the Becke exchange functional and the LYP correlation functional. SVWN requests the Slater exchange and the VWN functional, and is known in the literature by its synonym LSDA (Local Spincorrelation Density Approximation). LSDA is a synonym for SVWN. Some other software packages with DFT facilities use the equivalent of SVWN5 when "LSDA" is requested. Check the documentation

carefully for all packages when making comparisons. Correlation Functional Variations. The following correlation functionals combine local

and non-local terms from different correlation functionals: • •

VP86: VWN5 local and P86 non-local correlation functional. V5LYP: VWN5 local and LYP non-local correlation functional.

Standalone Functionals. The following functionals are self-contained and are not

combined with any other functional keyword components: •

•

VSXC: van Voorhis and Scuseria's τ-dependant gradient-corrected correlation

functional [481]. HCTH/*: Handy's family functional including gradient-corrected correlation [482,483,484]. HCTH refers to HCTH/407, HCTH93 to HCTH/93, HCTH147 to HCTH/147, and HCTH407 to HCTH/407. Note that the related HCTH/120 functional is not implemented.

Hybrid Functionals. Three hybrid functionals, which include a mixture of Hartree-Fock

exchange with DFT exchange-correlation, are available via keywords: •

•

Becke Three Parameter Hybrid Functionals. These functionals have the form devised by Becke in 1993 [79]: A*EXSlater +(1-A)*EXHF+B*ΔEXBecke+ECVWN+C*ΔECnon-local


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•

•

• •

•

•

•

•

• • •

• • • •

where A, B, and C are the constants determined by Becke via fitting to the G1 molecule set. There are several variations of this hybrid functional. B3LYP uses the non-local correlation provided by the LYP expression, and VWN functional III for local correlation (not functional V). Note that since LYP includes both local and nonVWN local terms, the correlation functional used is actually: C*ECLYP +(1-C)*E C In other words, VWN is used to provide the excess local correlation required, since LYP contains a local term essentially equivalent to VWN. B3P86 specifies the same functional with the non-local correlation provided by Perdew 86, and B3PW91 specifies this functional with the non-local correlation provided by Perdew/Wang 91. Becke One Parameter Hybrid Functionals. The B1B95 keyword is used to specify Becke's one-parameter hybrid functional as defined in the original paper [480]. The program also provides other, similar one parameter hybrid functionals, as implemented by Adamo and Barone [480,485]. In one variation, B1LYP, the

LYP correlation functional used (as Perdew-Wang described for B3LYP above). Another version, MPW1PW91 , usesismodified exchange and Perdew-Wang 91 correlation [468 ]. Becke's 1998 revisions to B97 [486,487]. The keyword is B98, and it implements equation 2c in reference [487]. Handy, Tozer and coworkers modification to B97: B971 [482]. Wilson, Bradley and Tozer's modification to B97: B972 [488]. The 1997 hybrid functional of Perdew, Burke and Ernzerhof [472]. The keyword is PBE1PBE. This functional uses 25% exchange and 75% correlation weighting. Half-and-half Functionals, which implement the following functionals: 0.5*EXHF + 0.5*EXLSDA + ECLYP BHandH: HF

LSDA

Becke88

LYP

X BHandHLYP + 0.5*E + 0.5*ΔEX functionals + EC proposed by Note that these: are 0.5*E not theX same as the "half-and-half"

Becke ( J. Chem. Phys. 98, 1372 (1993)). These functionals are included for backward-compatibility only. User-Defined Models. Gaussian 03 can use any model of the general form:

P2EXHF + P1(P4EXSlater + P3ΔExnon-local) + P6EClocal + P5ΔECnon-local The only available local exchange method is Slater (S), which should be used when only local exchange is desired. Any combinable non-local exchange functional and combinable correlation functional may be used (as listed previously). You specify the values of the six parameters with various non-standard options to the program: •

IOp(3/76=mmmmmnnnnn) sets P1 to mmmmm/10000 and P2 to nnnnn/10000. P1 is

usually set to either 0.0 or 1.0, depending on whether an exchange functional is desired or not, and any scaling is accomplished using P3 and P4.


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• •

IOp(3/77=mmmmmnnnnn) sets P3 to mmmmm/10000 and P4 to nnnnn/10000. IOp(3/78=mmmmmnnnnn) sets P5 to mmmmm/10000 and P6 to nnnnn/10000.

For example, IOp(3/76=1000005000 ) sets P1 to 1.0 and P2 to 0.5. Note that all values must be expressed using five digits, adding any necessary leading zeros. Here is a route section specifying the functional corresponding to the B3LYP keyword: # BLYP IOp(3/76=1000002000) IOp(3/77=0720008000) IOp(3/78=0810010000)

ACCURACY CONSIDERATIONS

A DFT calculation adds an additional step to each major phase of a Hartree-Fock calculation. This step is a numerical integration of the functional (or various derivatives of the functional). Thus in addition to the sources of numerical error in Hartree-Fock calculations (integral accuracy, SCF convergence, CPHF convergence), the accuracy of DFT calculations also depends on number of points used in the numerical integration. The "fine" integration grid (corresponding to Integral=FineGrid) is the default in Gaussian 03. This grid greatly enhances calculation accuracy at minimal additional cost. We do not recommend using any smaller grid in production DFT calculations. Note also that it is important to use the same grid for all calculations where you intend to compare energies (e.g., computing energy differences, heats of formation, and so on). Larger grids are available when needed (e.g. tight optimization of certain kinds of systems). An alternate grid may be selected by including Integral=(Grid= N ) in the route section (see the discussion of the Integral keyword for details).

Energies, analytic gradients, and analytic frequencies; ADMP calculations.

IOp, Int=Grid, Stable, TD, DenFit

The energy is reported in DFT calculations in a form similar to that of Hartree-Fock calculations. Here is the energy output from a B3LYP calculation: SCF Done:

E(RB+HF-LYP) =

-75.3197099428

A.U. after

5 cycles

The item in parentheses following the E denotes the method used to obtain the energy. The output from a BLYP calculation is labeled similarly:


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SCF Done:

E(RB-LYP) =

-75.2867073414

A.U. after

5 cycles

Molecular Mechanics Methods

There are three molecular mechanics methods available in Gaussian. They were implemented for use in ONIOM calculations, but they are also available as independent methods. No basis set keyword should be specified with these keywords. The following force fields are available: AMBER : The AMBER force field as described in [37]. The actual parameters

( parm96.dat ) have been updated slightly since the publication of this paper. We use this current version from the AMBER web site (amber.scripps.edu). DREIDING: The DREIDING force field as described in [38]. UFF: The UFF force field as described in [39].


Unless set in the molecule specification input, no charges are assigned to atoms by default when using any molecular mechanics force field. Options are available to estimate charges at the initial point using the QEq algorithm under control of the following options for any of the mechanics keywords: QEq





by the user in the input stream for the current job (or a previous job when reading


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parameters from the checkpoint file). By default, when no relevant option is given, the hard-wired parameters are the only ones used. HardFirst

Read additional parameters from the input stream, with hard-wired parameters having priority over thehard-wired read-in, soft ones. Hence, read-in parameters are used if there is no corresponding value. Note that wildcards matches within theonly hardwared parameter set take precidence over soft parameters, even when the latter contains an exact match for the same item. Use SoftFirst if you want to override hard-wired parameter matches. SoftFirst







found.


LastEquiv



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O-O--0.5




ONIOM, Geom=Connect


Unless otherwise indicated, distances are in Angstroms, angles are in degrees, energies are in Kcal/mol and charges are in atomic units. Function equivalencies to those found in standard force fields are indicated in parentheses. In equations, R refers to distances and θ refers to angles. Wildcards may be used in any function definition. They are indicated by a 0 or an asterisk. In MM force fields, the non-bonded (Vanderwaals and electrostatic) interactions are evaluated for every possible pair of atoms. However, interactions between pairs of atoms that are separated by three bonds or less are usually scaled down (in most force fields, using a factor 0.0 for pairs separated by one or two bonds, and some value between 0.0 and 1.0 for pairs that are separated by three bonds). There are a number of ways to implement the calculation of non-bonded interactions. We follow a two-step procedure. First, we calculate the interactions between all pairs, without taking the scaling into account. In this step, we can use computationally efficient (linear scaling) algorithms. In the second step, we subtract out the contributions that


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should have been scaled, but were included in the first step. Since this involves only pairs that are close to each other based on the connectivity, the computer time for this step scales again linearly with the size of the system. Although at first sight it seems that too much work is done, the overall algorithm is the more efficient than the alternatives. In softand force input,entry the NBDir entry corresponds to the of all thethe pairs, thefield NBTerm is usedfunction for the subsequent subtraction ofcalculation the individual pairs. However, to make things easier, you can specify just the non-bonded master function NonBon, which is automatically expanded into the actual functions NBDir and NBTerm during pre-processing. Vanderwaals parameters, used for NBDir and NBTerm (See MMFF94 below for MMFF94-type Vanderwaals parameters). VDW Bond-length Well-depth






0 1 2 3 4

No Vanderwaals Arithmetic (as for Dreiding) Geometric (as for UFF) Arithmetic (as for Amber) MMFF94-type Vanderwaals


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C-Type is the Coulomb type:

0 1 2 3

No Coulomb 1/R 1/R 2 1/R buffered (MMFF94)

V-Cutoff and C-Cutoff are the Vanderwaals and Coulomb cutoffs (respectively): 0 No cutoff

>0 <0

Hard cutoff Soft cutoff

VScale1-3 are Vanderwaals scale factors for 1 to 3 bond separated pairs. CScale1-3 are








Step down table


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Table Original-atom-type Stepping-down-type(s).










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with EffChg.


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Mag 4 NPaths


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PO1-PO4 Phase offsets Mag 1...Mag 4 V/2 magnitudes NPaths Number of paths (if < 0, determined on-the-fly).

Dreiding torsion (Dreiding [13]): V *[1-cos( Period *(θ- PO))]/(2* NPaths) DreiTrs Atom-type1 Atom-type2 Atom-type3 Atom-type4 V PO Period NPaths V Barrier height V PO Phase offset Period Periodicity NPaths Number of paths (if < 0, determined on-the-fly).







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•

•







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-1 -2 -3



-1 -2 -3

0 ≤ θ ≤ 45 45 < θ ≤ 135 135 < θ ≤ 180


-i-n


For dihedral angles, one or two substructures may be used (e.g., AmbTrs-1-2). Use a zero for the first substructure to specify only the second substructure.


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First substructure : • • • •

-0 -1 -2

Skip this substructure (substructure "wildcard") Single central bond: 0.00 ≤ bond order < 1.50 Double central bond: 1.50 ≤ bond order < 2.50

Triple central bond: bond order ≥ 2.50 Second substructure: • • •

-3

-i-1 -i-2 -i-3



H_ C_2 C_2 * * *

C_2 360.0 1.08 C_2 350.0 1.50 C_2 500.0 1.40 C_2 * 50.0 120.0 C_2 C_2 * 5.0 180.0 C_2 C_2 * 45.0 180.0

2.0 -1.0 2.0 -1.0

Huckel This method keyword requests an extended Hückel calculation [503,504,505,506,507]. ExtendedHuckel is a synonym for this keyword. No basis set keyword should be specified.

Hoffmann

Requests an Extended Huckel calculation using the default parameter set from the Huckel group. Muller

Requests an Extended Huckel calculation using parameters collected by Edgar Muller. Guess

Requests an Extended Huckel calculation using the modified parameters used for Guess=Huckel [508,509,510].


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Energies, "analytic" gradients and numerical frequencies.

The energy appears in the output file as follows (followed by the x, y, and z components of the dipole moment): Huckel eigenvalues -- -1.245 -0.637 -0.558 -0.544 -0.043 Energy= -5.968836513622 NIter= 0. Dipole moment= 0.000000 0.000000 0.000000

0.352

The energy is as defined by this semi-empirical model. Note that energy differences computed from the values in semi-empirical calculations are in Hartrees and may be compared directly with energy differences computed from jobs using other methods.

Guess=Huckel

External Requests a calculation using an external program. This mechanism is primarily intended to facilitate the use of external programs to provide the low-level calculations in ONIOM calculations, but can also be used to conduct geometry optimizations using Gaussian's optimizer with external programs providing the function values and derivatives. Gaussian uses a standardized interface to run an external program to produce an energy

(and optionally a dipole moment or forces) at each geometry. A text file is produced with the current structure, and a script named Gau_External is run. This script is expected to: • • •

Convert the text file into input for another program. Run that program. Convert the results into a standard text form for recovery by Gaussian.

The script is passed two parameters: the name of the file Gaussian has prepared as input for the external program (the input file), and the name of the file which should be read in after the external program completes (the output file). INPUT FILE FORMAT


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The input file has the following format: #atoms derivatives-requested charge & spinlow charge & spinmedium atomic# x y z MM-charge atom.

charge & spinhigh Repeated for each

The first line specifies the number of atoms in the molecule, what derivatives are to be computed (0=energy only, 1=first derivatives, 2=second derivatives), and the molecule's charge and spin multiplicity. The remaining lines specify the atomic number, coordinates and molecular mechanics charge for each atom. OUTPUT FILE FORMAT

The output file is in fixed format, and has the following information: energy dipole-moment(xyz) force on atom (xyz)

Format: 4D20.12 Format: 3D20.12 Repeated for each atom.

Hessian (xyz)

Format: 3D20.12 Repeated as needed.

The second section is present only if first derivatives or frequencies were requested, and the final section is present only if frequencies were requested. In the latter case, the Hessian is given in lower triangular form: αij, i=1 to N , j=1 to i.

ExtraBasis ExtraDensityBasis These keywords indicate that additional basis functions are to be added to the basis set or density fitting basis set specified in the route section for the calculation (respectively). These basis functions appear in a separate section in the input stream, using any of the valid formats (which are described in detail in the discussion of the Gen keyword). is most useful for supplying basis functions for elements undefined in a standard basis set. It cannot be used to replace a definition within a built-in basis set, and attempting to do so will result in an error. All basis functions specified with this keyword are added to the ones in the basis set specified in the route section. For these reasons, Gen is often easier to use than ExtraBasis; consult the description for that keyword before deciding to use this one. ExtraBasis

ExtraDensityBasis

is ignored if no density fitting basis is specified in the route.


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Gen, Pseudo, GenECP, GFInput, GFPrint

The following job uses the 6-31G(d,p) basis set along with an additional diffuse function on all of the carbon atoms: # HF/6-31G(d,p) ExtraBasis ...

title section molecule specification C 0 SP 1 1.00 0.4380000000D-01 ****

0.1000000000D+01

0.1000000000D+01

The following job supplies additional functions for both the basis set and for density fitting: #p rblyp/6-31g*/dga1 extrabasis extradensitybasis 6d HCl using the internally stored 6-31g* AO basis & DGA1 fitting set, adding f functions to the AO basis, and f & g fitting functions 0,1 cl h,1,1.29 ! here are some extra AO polarization functions cl 0 F 10.7500000000D+00 1.00 0.000000000000 0.1000000000D+01 **** h 0 p 1 1.00 0.000000000000 0.1612777588D+00 0.1000000000D+01 **** ! here are some extra fitting functions. cl 0 f 1 1.5 g 1 1.5 **** h 0 spd 1 0.32 ****

Frozen Core Options


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These options specify which inner orbitals are frozen in post-SCF calculations. Gaussian 03 adds some additional options to the ones already available in the program [489].

FC

This indicates "frozen-core," and it implies that inner-shells are excluded from the correlation calculation. This is the default calculation mode. Note that FC, Full, RW and Window are mutually exclusive. It is which is equivalent to FreezeG2 for the 6-31G and 6-311G basis sets and to FreezeNobleGasCore for all other basis sets, except that the outer s and p core orbitals of 3rd row and later alkalai and alkalai earth atoms are not frozen (in accord with the G2/G3 conventions). FreezeNobleGasCore

In post-SCF calculations the largest noble gas core is frozen. FrzNGC is a synonym for this option. FreezeInnerNobleGasCore

In post-SCF calculations, the next to largest noble gas core is frozen. That is, the outermost core orbitals are retained. FrzINGC and FC1 are synonyms for this option. FreezeG2

Freeze orbitals according to the G2 row convention: orbitalsand of alkalai main group frozen, but the outer sp core of 3rd and laterdalkalai earthelements elements are are kept in the valence. Full

This specifies that all electrons be included in a correlation calculation. RW

The "read window" option means that specific information about which orbitals are retained in the post-SCF calculation will be given in the input file. The additional input section consists of a line specifying the starting and ending orbitals to be retained, followed a blank line. A value offirst zeroorbital indicates the first (ormlast orbital, depending where it isbyused. If the value for the is negative ), then the highest m on orbitals are retained; if the value for the last orbital is negative (-n), then the highest n orbitals are frozen. If m is positive and n is omitted, n defaults to 0. If m is negative and n is omitted, then the highest |m| occupied and lowest |m| virtual orbitals are retained. Here are some examples for a calculation on C4H4:


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0,0 is equivalent to Full. 5,0 freezes the 4 core orbitals and keeps all virtual orbitals (equivalent to FC if the basis

has a single zeta core). 5,-4 freezes the four core orbitals and the highest four virtual orbitals. This is the

appropriate frozen-core for a basis with a double-zeta core.

6,22 retains orbitals 6 through 22 in the post-SCF. For example, since C4H4 has 28

electrons, if this is a closed shell calculation, there will be 14 occupied orbitals, 5 of which will be frozen, so the post-SCF calculation will involve 9 occupied orbitals (orbitals 6-14) and 8 virtual orbitals (orbitals 15-22). -6 retains orbitals 9 through 20. ReadWindow is a synonym for RW. Window=(m[,n])

Performs the same function as the ReadWindow option, but takes its input as parameters in the route section rather than from the input stream. ChkWindow

The window read in during a previous job is recovered from the checkpoint file. ListWindow

Causes a list of orbitals to freeze (omit from post-SCF calculations) to be read from the input stream, terminated by a blank line. Two lists are read for unrestricted calculations. A range of orbitals can be specified, e.g.: 2 7-10 14

Field The Field keyword requests that a finite field be added to calculation. In Gaussian 03, the field can either involve electric multipoles (through hexadecapoles) or a Fermi contact term. Field requires a parameter in one of these two formats: M ± N or F(M ) N

where M designates a multipole, and F(M ) designates a Fermi contact perturbation for atom M (following the ordering in the molecule specification section of the input file). N *0.0001 specifies the magnitude of the field in atomic units in the first format, and specifies the magnitude of the Fermi contact perturbation in the second format.


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Thus, Field=X+10 applies an electric dipole field in the X direction of 0.001 au, while Field=XXYZ-20 applies the indicated hexadecapole field with magnitude 0.0020 au and direction opposite to the default (which is determined by the standard orientation). Similarly, Field=F(3)27 applies a perturbation of 0.0027 times the spin density on atom 3. Note that the coefficients are those of the Cartesian operator matrices; be careful of the choice of sign convention when interpreting the results. All parameters are in the input orientation. The field specification parameter may be placed among any other options as desired. Archiving is disabled when Field is specified.

Read

Reads the coefficients of 34 electric multipole components from the input stream in free format. OldRead

Reads the coefficients of 35 electric multipole components from the input stream, in the old style format (including the monopole term): using format 3D20.10 (the first component is a charge). RWF

Takes the 35 multipole components from the read-write file. ERWF

Extracts only the three electric dipole field components from the read-write file. Checkpoint

Reads the 35 multipole components from the checkpoint file. Chk is a synonym for Checkpoint. EChk

Extracts only the three electric dipole field components from the checkpoint file.

Single point energy, geometry optimizations, and Force and Scan calculations. LIMITATIONS


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Note that if symmetry is left on during a GVB calculation, the finite field will or will not lead to correct numerical derivatives, depending on whether the selected field breaks molecular symmetry. To be safe, use Guess=NoSymm whenever using Field with GVB.

To perform geometry optimizations in the presence of an electric field, you must use Opt=Z-Matrix NoSymm keywords and define the input geometry either in traditional Zmatrix coordinates or symbolic Cartesian coordinates. Here is an example using a Zmatrix: # RHF/3-21G Field=x+60 Opt=Z-Matrix NoSymm Z-Matrix optimization 0 C H H H H

1 1 1 1 1

B1 B2 B3 B4

B1 B2 B3 B4 A1 A2 A3 D1 D2

2 2 2

A1 A2 A3

3 3

D1 D2

1.070000 1.070000 1.070000 1.070000 109.471203 109.471203 109.471231 120.000015 -119.999993

Here is an example using symbolic Cartesian coordinates: # HF/6-31G(d) Opt=Z-Matrix Field=z-50 NoSymm Symbolic Cartesian coordinates optimization 0 1 O 0 H 0 H 0

x1 y1 z1 x2 y2 z2 x3 y3 z3

x1=0.0 y1=0.0 z1=0.12 x2=0.0 y2=0.75 z2=-0.46 x3=0.0 y3=-0.75 z3=-0.46


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FMM Force the use of the fast multipole method [29,30,31,32,33,490,491,492] if possible. The use of FMM is automated in Gaussian 03. The NoFMM keyword may be used to prevent this facility from being used. Gaussian 03 generally turns on the FMM facility when using it provides even a modest performance gain (say, 1.2x). For a molecule with no symmetry, FMM is enabled for nonsymmetric molecules with 60 atoms or more for both Hartree-Fock and DFT. For molecules with high symmetry, FMM is enabled for Hartree-Fock and hybrid DFT above 240 atoms and for pure DFT above 360 atoms. For molecules with low (but non-zero) symmetry, intermediate thresholds are used. You will begin to see substantial performance improvements (2x or better) with another factor of two in system size.

Of course, the exact results will vary from case to case (compact systems show the least speedup; stretched out linear ones the most), but the defaults are very unlikely to enable FMM when it has a negative effect on performance and are also as unlikely to fail to enable it when it would be worth a factor of 1.5x or more. Thus, users are unlikely to need to control FMM by hand except for some very unusual special cases, such as nearly linear polypeptides and long carbon nanotubes.

LMax= N the maximum order multipole. The default is 25 (or 15 when SCF=Sleazy is Specifies

used). Levels= N

Specifies the number of levels to use in the FMM. The default is 8 for molecules and is adjusted dynamically for PBC. Tolerance= N

Specifies the accuracy level as 10-N. The default values for N are 8 for single point energy calculations and 10 for other calculation types. BoxLen= N

Sets the minimum box length (size) to N /10 Bohrs. By default, N is 30. AllNearField

Turn on all near-field in FMM.


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Energies, gradients and frequencies for HF, pure and hybrid DFT. This keyword may also be used within method specifications for ONIOM layers.

Sparse

Force This calculation type keyword requests a single calculation of the forces on the nuclei (i.e., the gradient of the energy). The dipole moment is also computed (as a proper analytic derivative of the energy for MP2, CC, QCI and CI) [202,447].

EnOnly

Compute the forces by numerically differentiating the energy once. It is the default for all methods for which analytic gradients are unavailable. Note that this procedure exhibits some numerical instability, so care must be taken that an optimal step size is specified for each case. Restart

Restarts numerical evaluation of the forces. StepSize= N

Sets the step size used in numerical differentiation to 0.0001* N . The units are Angstroms by default unless Units=Bohr has been specified. The default step size is 0.01 Å. StepSize is valid only in conjunction with EnOnly.

Analytic gradients are available for all SCF wavefunctions, all DFT methods, CIS, MP2, MP3, MP4(SDQ), CID, CISD, CCD, CCSD, QCISD, CASSCF, SAC-CI and all semiempirical methods. For other methods, the forces are determined by numerical differentiation.

The forces on the nuclei appears in the output as follows (this sample is from a calculation on water):


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***** AXES RESTORED TO ORIGINAL SET ***** ------------------------------------------------------------------Center Atomic Forces (Hartrees/Bohr) Number Number X Y Z ------------------------------------------------------------------1 8 -.049849321 .000000000 -.028780519 2 1 .046711997 .000000000 -.023346514 3 1 .003137324 .000000000 .052127033 ------------------------------------------------------------------MAX .052127033 RMS .031211490 ------------------------------------------------------------------Internal Coordinate Forces (Hartree/Bohr or radian) Cent Atom N1 Length/X N2 Alpha/Y N3 Beta/Z ------------------------------------------------------------------1 O 2 H 1 -.023347( 1) 3 H 1 -.023347( 2) 2 -.088273( 3) ------------------------------------------------------------------MAX .088272874 RMS .054412682

J

The forces are determined in the standard orientation, but are restored to the original (Zmatrix) set of axes before printing (as noted in the output). This is followed by the corresponding derivatives with respect to the internal coordinates (lengths and angles used in the Z-matrix) when internal coordinates are in use. The forces are followed in each case by their maximum and root-mean-square values.

Freq This calculation type keyword computes force constants and the resulting vibrational frequencies. Intensities are also computed. By default, the force constants are determined analytically if possible (for RHF, UHF, MP2, CIS, all DFT methods, and CASSCF), by single numerical differentiation for methods for which only first derivatives are available (MP3, MP4(SDQ), CID, CISD, CCD, QCISD, and all semi-empirical methods), and by double numerical differentiation for those methods for which only energies are available. Vibrational frequencies are computed by determining the second derivatives of the energy with respect to the Cartesian nuclear coordinates and then transforming to massweighted coordinates. This transformation is only valid at a stationary point! Thus, it is meaningless frequencies at any method used to forcompute frequency determination . geometry other than a stationary point for the

For example, computing 3-21G frequencies at a STO-3G optimized geometry produces meaningless results. It is also incorrect to compute frequencies for a correlated method using frozen-core at a structure optimized with all electrons correlated, or vice-versa. The recommended practice is to compute frequencies following a previous geometry


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optimization using the same method. This may be accomplished automatically by specifying both Opt and Freq within the route section for a job. Note also that the coupled perturbed Hartree-Fock (CPHF) method used in determining analytic frequencies is not physically meaningful if a lower energy wavefunction of the same spinwavefunctions. multiplicity exists. Use the Stable keyword to test the stability of Hartree-Fock and DFT FREQUENCY CALCULATION VARIATIONS

When frequencies are done analytically, polarizabilities are also computed automatically; when numerical differentiation is required (or requested with Freq=Numer), polarizabilities must be explicitly requested using the Polar keyword (e.g., QCISD Freq Polar). The VCD option may be used to compute the vibrational circular dichroism (VCD) intensities in addition to the normal frequency analysis at the Hartree-Fock and DFT levels [242]. Pre-resonance Raman intensities may be computed by specifying a Raman option, and also including CPHF=RdFreq within the route and specifying the desired frequency in the input file (see the examples for additional information). Frequency-dependent polarizabilities and hyperpolarizabilities may similarly be computed by including CPHF=RdFreq within the route (subject to their usual availability restrictions). Opt=CalcAll requests that analytic second derivatives be done at every The keyword point in a geometry optimization. Once the requested optimization has completed all the information necessary for a frequency analysis is available. Therefore, the frequency analysis is performed and the results of the calculation are archived as a frequency job.

You should specify alternative isotopes for frequency jobs using the standard method. However, the ReadIsotopes option is retained for rerunning completed calculations under different conditions (see the examples).

VCD

Compute the vibrational circular dichroism (VCD) intensities in addition to the normal frequency analysis [242]. This option is valid for Hartree-Fock and DFT methods. This option also computes optical rotations (see Polar=OptRot). Raman

Compute Raman intensities in addition to IR intensities. This is the default for HartreeFock. It may be specified for DFT and MP2 calculations in order to produce Raman


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intensities by numerical differentiation of dipole derivatives with respect to the electric field. For these methods, it is equivalent to NRaman. If CPHF=RdFreq is used, then Raman is equivalent to NNRaman for all methods. NRaman

Do by This numerically differentiating the analytic dipole derivatives withpolarizability respect to anderivatives electric field. is the default for CIS, DFT, and MP2 if Raman is requested but CPHF=RdFreq is not. NNRaman

Do polarizability derivatives by numerically differentiating the analytic polarizability with respect to nuclear coordinates. This is the default if Raman is requested along with CPHF=RdFreq. NoRaman

Skips the extra steps required to compute the Raman intensities during Hartree-Fock analytic frequency calculations, saving 10-30% in CPU time. VibRot

Analyze vibrational-rotational coupling [206,207,208,209,210,211,493,494,495]. Anharmonic

Do numerical differentiation along normal modes to compute zero-point energies, anharmonic frequencies [206,208,209,211,493,494,495], and anharmonic vibrationalrotational couplings if VibRot is also specified [207,210,212,213,214]. This option is only available for methods with analytic second derivatives: Hartree-Fock, DFT, CIS and MP2. ReadAnharm

Read an input section with additional parameters for the vibration-rotation coupling and/or anharmonic vibrational analysis (VibRot or Anharmonic options). Available input options are documented following the examples. ReadFC

Requests that the force constants from a previous frequency calculation be read from the checkpoint file, and the normal mode and thermochemical analysis be repeated, presumably using a different temperature, pressure, or isotopes, at minimal computational cost. Note that since the basis set is read from the checkpoint file, no general basis should Raman be input. If the option was specified in the previous job, then do not specify it again when using this option. HPModes

Include the high precision format (to five figures) vibrational frequency eigenvectors in the frequency output in addition to the normal three-figure output.


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InternalModes

Print normal modes as displacements in redundant internal coordinates. IntModes is a synonym for this option. Analytic

This that the second derivatives of the energy are toMP2, be computed analytically. This specifies option is available only for RHF, UHF, CIS, CASSCF, and all DFT methods, and it is the default for those cases. Numerical

This requests that the second derivatives of the energy are to be computed numerically using analytically calculated first derivatives. It can be used with any method for which gradients are available and is the default for those for which gradients but not second derivatives are available. Freq=Numer can be combined with Polar=Numer in one job step. EnOnly

This requests double numerical differentiation of energies to produce force constants. It is the default and only choice for those methods for which no analytic derivatives are available. EnergyOnly is a synonym for EnOnly. Cubic

Requests numerical differentiation of analytic second derivatives to produce third derivatives. Step= N

Specifies the step-size for numerical differentiation to be 0.0001* N (in Angstoms unless Units=Bohr Polar=Numer specified). If Freq=Numer combined, N also specifieshas thebeen step-size in the electric field. Theand default is 0.001 Å are for Hartree-Fock

and correlated Freq=Numer, 0.005 for GVB and CASSCF Freq=Numer, and 0.01 Å for Freq=EnOnly. For Freq=Anharmonic or Freq=VibRot, the default is 0.025. Restart

This option restarts a numerical frequency calculation after the last completed geometry (analytic frequency calculations are not restartable). A failed numerical frequency job may be restarted from its checkpoint file by simply repeating the route section of the original job, adding the Restart option to the Freq keyword. No other input is required. Projected For a point on a mass-weighted reaction path (IRC), compute the projected frequencies

for vibrations perpendicular to the path. For the projection, the gradient is used to compute the tangent to the path. Note that this computation is very sensitive to the accuracy of the structure and the path [496]. Accordingly, the geometry should be specified to at least 5 significant digits. This computation is not meaningful at a minimum.


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HinderedRotor

Requests the identification of internal rotation modes during the harmonic vibrational analysis [497]. If any normal modes are identified as internal rotation, hindered or free, the thermodynamic functions are corrected. The identification of the rotating groups is made possible by the use of redundant internal coordinates. Thus, redundant internal must such coordinates be used for the HinderedRotor option to function properly. some structures, as transition states, may have a specific bonding pattern Because not automatically recognized, the set of redundant internal coordinates may need to be altered via the Geom=Modify keyword.

If the force constants are available on a previously generated checkpoint file, additional vibrational/internal rotation analyses may be performed by specifying Freq=(ReadFC, HinderedRotor). Since Opt=CalcAll automatically performs a vibrational analysis on the optimized structure, Opt=(CalcAll, HinderedRotor) may also be used. ModRedundant

Read-in modifications redundant coordinates with InternalModes ). Note to that the sameinternal coordinates are used(i.e., for for bothuse optimization and normal mode analysis in an Opt Freq, for which this is the same as Opt=ModRedundant. See the discussion of the Opt keyword for details on the input format. ReadIsotopes

Specify alternate temperature, pressure, and/or isotopes (the defaults are 298.15 K, 1 atmosphere, and the most abundant isotopes). By default, this option uses temperature, pressure, and scale factor specified in the route section. Alternatively, this information can appear in a separate input section having the format: temp pressure [scale] isotope mass for atom 1 isotope mass for atom 2 ... isotope mass for atom n

Must be real numbers.

where temp, pressure, and scale are the desired temperature, pressure, and an optional scale factor for frequency data when used for thermochemical analysis (the default is unscaled). The remaining lines hold the isotope masses for the various atoms in the molecule, arranged in the same order as they appeared in the molecule specification section. If integers are used to specify the atomic masses, the program will automatically 18

use actual exact isotopic mass (e.g., 18 specifies O , and Gaussian usesthe thecorresponding value 17.99916).

Analytic frequencies are available for the HF, DFT, MP2, CIS and CASSCF methods. Numerical frequencies are available for MP3, MP4(SDQ), CID, CISD, CCD, CCSD and QCISD.


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Polar, Opt, Stable

Frequency Output. The basic components of the output from a frequency calculation are

discussed in detail in chapter 4 of Exploring Chemistry with Electronic Structure Methods [308]. You may be surprised to see output that looks like it belongs to a geometry optimization at the beginning of a frequency job: GradGradGradGradGradGradGradGradGradGradGradGradGradGradGrad Berny optimization. Initialization pass.

Link 103, which performs geometry optimizations, is executed at the beginning and end of all frequency calculations. This is done so that the quadratic optimization step can be computed using the correct second derivatives. Occasionally an optimization will complete according to the normal criterion using the approximate Hessian matrix, but the step size is actually larger than the convergence criterion when the correct second derivatives are used. The next step is printed at the end of a frequency calculation so that such problems can be identified. If you think this concern is applicable, use Opt=CalcAll instead of Freq in the route section of the job, which will complete the optimization if the geometry is determined not to have fully converged (usually, given the full second derivative matrix near a stationary point, only one additional optimization step is needed), and will automatically perform a frequency analysis at the final structure. Specifying #P in the route section produces some additional output for frequency calculations. Of most importance are the polarizability and hyperpolarizability tensors (they still may be found in the archive entry in normal print-level jobs). They are presented in lower triangular and lower tetrahedral order, respectively (i.e., αXX,αXY, αYY, αXZ, αYZ,αZZ and βXXX, βXXY, βXYY, βYYY, βXXZ, βXYZ, βYYZ, βXZZ, βYZZ, βZZZ), in the standard orientation: Dipole = 2.37312183D-16 -6.66133815D-16 -9.39281319D-01 Polarizability= 7.83427191D-01 1.60008472D-15 6.80285860D+00 HyperPolar

2.72397709D-16 4.17080415D-16 3.62729494D+00 =-3.11369582D-17 3.08796953D-16 -6.27350412D-14 5.55019858D-14 -7.26773439D-01 -1.09052038D-14 -2.07727337D+01 4.49920497D-16 -1.40402516D-13 -1.10991697D+01

#P also produces a bar-graph of the simulated spectra for small cases.


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Thermochemistry analysis follows the frequency and normal mode data. The zero-point energy output in Gaussian has been expanded over that produced by older versions: Zero-point correction= .023261 (Hartree/Particle) Thermal correction to Energy= .026094 Thermal correction to Enthalpy= .027038 Thermal correction to Gibbs Free Energy= .052698 Sum of electronic and zero-point Energies=-527.492585 E 0=E elec+ZPE Sum of electronic and thermal Energies= -527.489751 E= E 0+ E vib+ E +E rot trans Sum of electronic and thermal Enthalpies=-527.488807 H=E+RT Sum of electronic and thermal Free Energies=-527.463147 G=H-TS

The raw zero-point energy correction and the thermal corrections to the total energy, enthalpy, and Gibbs free energy (all of which include the zero-point energy) are listed, followed by the corresponding corrected energy. The analysis uses the standard expressions for an ideal gas in the canonical ensemble. Details can be found in McQuarrie [498] and other standard statistical mechanics texts. In the output, the various quantities are labeled as follows: E (Thermal) CV S Q

Contributions to the thermal energy correction Constant volume molar heat capacity Entropy Partition function

The thermochemistry analysis treats all modes other than the free rotations and translations harmonic Forand molecules havingathindered internal rotations, can produce as slight errors vibrations. in the energy heat capacity room temperatures and canthis have a significant effect on the entropy. The contributions of any very low frequency vibrational modes are listed separately so that if they are group rotations and high accuracy is needed, their harmonic contributions can be subtracted from the totals, and their correctly computed contributions included. Expressions for hindered rotational contributions to these terms can be found in Benson [499]. The partition functions are also computed, with both the bottom of the vibrational well and the lowest (zero-point) vibrational state as reference. Pre-resonance Raman. This calculation type is requested with one of the Raman

options in chosen combination with CPHF=RdFreq. The frequency specified for the latter should be as follows: •

•

Determine the difference in frequency between the peak of interest in the Raman spectrum and the incident light used in the experiment. Perform a TD calculation using a DFT method in order to determine the predicted location of the same peak.


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•

Specify a frequency for CPHF=RdFreq which is shifted from the predicted peak by the same amount as the incident light differs from the observed peak.

Pre-resonance Raman results are reported as additional rows within the normal frequency tables: Harmonic frequencies (cm**-1), IR intensities (KM/Mole), Raman scattering activities (A**4/AMU), depolarization ratios for plane and unpolarized incident light, reduced masses (AMU), force constants (mDyne/A), and normal coordinates: 1 B1 Frequencies -- 1315.8011 Red. masses -1.3435 Frc consts -1.3704 IR Inten -7.6649 Raman Activ -0.0260 Depolar (P) -0.7500 Depolar (U) -0.8571 RamAct Fr= 1-0.0260 Dep-P Fr= 1-0.7500 Dep-U Fr= 1-0.8571 RamAct Fr= 2-0.0023 Dep-P Fr= 2-0.7500 Dep-U Fr= 2-0.8571

Vibration-Rotation Coupling Output. If the VibRot option is specified, then the

harmonic vibrational-rotational analysis appears immediately after the normal thermochemistry analysis in the output, introduced by this header: Vibro-Rotational Analysis at the Harmonic level

If anharmonic analysis is requested as well (i.e., VibRot and Anharmonic are both specified), then the anharmonic vibrational-rotational analysis results follow the harmonic ones, introduced by the following header 2nd order Perturbative Anharmonic Analysis

Anharmonic Frequency Calculations. Freq=Anharmonic jobs product additional

output following the normal frequency output. (It follows the vibration-rotation coupling output if this was specified as well.) We will briefly consider the most important items within it here. This output displays the equilibrium geometry (i.e., the minimum on the potential energy surface), followed by the anharmonic vibrationally averaged structure at 0 K: Internal coordinates for the Equilibrium structure (Se) Interatomic distances: 1 2 3 4 1 C 0.000000


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2 3 4

O H H

1.220000 1.080000 1.080000

O2-C1-H3=120. O2-H3-H4= 62.0127

0.000000 1.993088 0.000000 1.993088 1.870615 0.000000 Interatomic angles: O2-C1-H4=120. H3-C1-H4=120.

Dihedral angles: H4-C1-H3-O2= 180. Internal coordinates for the vibr.aver. structure at 0K (Sz) Interatomic distances: 1 2 3 4 1 C 0.000000 2 O 1.223954 0.000000 3 H 1.093363 2.007355 0.000000 4 H 1.093363 2.007355 1.894824 0.000000 Interatomic angles: O2-C1-H3=119.9442 O2-C1-H4=119.9442 H3-C1-H4=120.1116 O2-H3-H4= 61.8377 Dihedral angles: H4-C1-H3-O2= 180.

Note that the bond lengths are slightly longer in the latter structure. The anharmonic zero point energy is given shortly thereafter in the output, preceded by its component terms: Zero Point Terms Harmonic ZPE (cm-1) Sum(Xij) (cm-1) 3rd der.Anh.E0 (cm-1) 4th der.Anh.E0 (cm-1) Vibr.Rot.E0 (cm-1) Anharmonic ZPE (cm-1)

= = = = = =

6339.70913 -79.34418 -24.91960 23.36569 -4.77806 6254.03298

The anharmonic frequencies themselves appear just a bit later in this table, in the column labeled : E(anharm) Vibrational Energies and Rotational Constants (cm-1) Mode(Quanta) E(harm) E(anharm) Aa(z) Ba(x) Equilibrium Geometry 9.560323 1.288616 Ground State 6339.709 6254.033 9.425702 1.283838 Fundamental Bands (DE w.r.t. Ground State) 1(1) 3180.793 3008.554 9.244416 1.283898 2(1) 1839.248 1805.679 9.432233 1.280472 3(1) 1661.905 1625.622 9.467760 1.288838 4(1) 1315.801 1292.782 7.968990 1.271489 5(1) 3292.300 3172.585 9.311674 1.282911 6(1)

1389.371

1365.996

10.859898

1.285869

Ca(y) 1.135528 1.125877 1.123734 1.118196 1.123277 1.126802 1.124406 1.119543

The harmonic frequencies are also listed for convenience. Rerunning a Frequency Calculation with Different Thermochemistry Parameters.

The following two-step job contains an initial frequency calculation followed by a second thermochemistry analysis using a different temperature, pressure, and selection of isotopes:


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%Chk=freq # HF/6-31G(d,p) Freq Test Frequencies at STP

molecule specification --Link1-%Chk=freq %NoSave # HF/6-31G(d,p) Freq(ReadIso,ReadFC) Geom=Check Test Repeat at 300 K 0,1

300.0 1.0 16 2 3 ...

Note also that the freqchk utility may be used to rerun the thermochemical analysis from the frequency data stored in a Gaussian checkpoint file. ADDITIONAL INPUT FOR FREQ=READANHARM

This input is read in a separate section which can contain the following keywords: Fermi

Also perform a vibrational averaging of isotropic hyperfine couplings. PrintGeom

Print the geometries at which properties for vibrational averaging are computed. TolFre= x

Minimum frequency difference (cm-1) for Fermi and Darling-Dennison resonances (default 10.0). Must be a real number. TolCor= x -1

-3

Threshold (cm ) on Coriolis couplings (default 10 ). Must be a real number. ScHarm= x

Scaling factor for linear scaling of harmonic frequencies (1.0 x 10-5 for B3LYP/631+G(d)). Must be a real number. By default, the value from the normal Scale keyword is used.


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G1 G2 G2MP2 G3 G3MP2 G3B3 G3MP2B3 These method keywords request the Gaussian-1 (more colloquially known as G1) [80,81], Gaussian-2 (G2) [82], and Gaussian-3 (G3) [84] methods for computing very accurate energies. G2MP2 requests the modified version of G2 known as G2(MP2), which uses MP2 instead of MP4 for the basis set extension corrections [83], and is nearly as accurate as the full G2 method at substantially reduced computational cost. G3MP3 requests the similarly modified G3(MP2) method [85]. The G3 variants using B3LYP structures and frequencies [86] are requested with the G3B3 and G3MP2B3 keywords. All of these methods are complex energy computations involving several pre-defined calculations on the specified molecular system. All of the distinct steps are performed automatically when one of these keywords is specified, and the final computed energy value is displayed in the output. No basis set keyword should be specified with these keywords. Either of the Opt=Maxcyc=n or QCISD=Maxcyc=n keywords may be used in conjunction with any of the these keywords to specify the maximum number of optimization or QCISD cycles, respectively. You should specify alternative isotopes for these jobs using the standard method. However, the ReadIsotopes option is retained for rerunning completed calculations under different conditions (see the examples).

ReadIsotopes

Specify alternate temperature, pressure, and/or isotopes (the defaults are 298.15 K, 1 atmosphere, and the most abundant isotopes). This information appears in a separate input section having the format:


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temp pressure [scale] isotope mass for atom 1 isotope mass for atom 2 ... isotope mass for atom n


temp, pressure, and scale are the desired temperature, pressure, and an optional where scale factor for frequency data when used for thermochemical analysis (the default value for the corresponding model is used if scale is omitted or set to 0.0); these values must be real numbers. The remaining lines hold the isotope masses for the various atoms in the molecule, arranged in the same order as they appeared in the molecule specification section. If integers are used to specify the atomic masses, the program will automatically use the corresponding actual exact mass (e.g., 18 specifies O18, and Gaussian uses the value 17.99916). Restart

Resume a partially-completed calculation from its checkpoint file. When used in ReadIso, this option allows for the rapid computation of the energy combination with using different thermochemistry parameters and/or isotope selections. StartMP2

Assume that the specified checkpoint file contains the results of a Hartree-Fock frequency calculation at the HF/6-31G* optimized structure, and begins the G2 calculation from that point (implies Geom=AllCheck ).

Calculation Summary Output. After all of the output for the component job steps,

Gaussian prints a table of results for these methods. Here is the output from a G2

calculation:

Temperature= E(ZPE)= E(QCISD(T))= DE(Plus)= G1(0 K)= G1 Enthalpy= E(Delta-G2)= G2(0 K)= G2 Enthalpy=

298.150000 .020511 -76.276078 -.010827 -76.328339 -76.324559 -.008275 -76.332054 -76.328274

Pressure= E(Thermal)= E(Empiric)= DE(2DF)= G1 Energy= G1 Free Energy= E(G2-Empiric)= G2 Energy= G2 Free Energy=

1.000000 .023346 -.024560 -.037385 -76.325503 -76.303182 .004560 -76.329219 -76.306897

The temperature and pressure appear first, followed by the various components used to compute the G2 energy. The output concludes with the G2 energy at 0 K and at the specified temperature (the latter includes a full thermal correction rather than just the zero-point energy correction), and (in the final output line) the G2 theory predictions for the enthalpy and Gibbs free energy (both computed using the thermal-corrected G2 energy). (Note that the same quantities predicted at the G1 level are also printed in this summary section.)


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The energy labels thus have the following meanings (G2 is used as an example): G2 (0 K)

Zero-point-corrected electronic energy: E0 = Eelec + ZPE G2 Energy Thermal-corrected energy: E = E0 + Etrans + Erot + Evib G2 Enthalpy

Enthalpy computed using the G2 predicted energy: H = E + RT G2 Free Energy

Gibbs Free Energy computed using the G2 predicted energy: G = H - TS Rerunning the Calculation at a Different Temperature. The following two-step job

illustrates the method for running a second (very rapid) G2 calculation at a different temperature. This job computes the G2 energy at 298.15 K and then again at 300 K: %Chk=formald # G2 Test G2 on formaldehyde 0 1 molecule specification --Link1-%Chk=formald %NoSave # G2(Restart,ReadIso) Geom=Check Repeat at 300 K 0,1 300.0 1.0

isotope specifications

Gen GenECP

A set of "standard" basis sets is stored internally in Gaussian (see the "Basis Sets" section earlier in this chapter); these basis sets may be specified by including the appropriate keyword within the route section for the calculation. The Gen keyword allows a userspecified basis set to be used in a Gaussian calculation. It is used in the place of a basis


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set keyword or a density fitting basis set keyword. In this case, the basis set description must be provided as input (in a separate basis set input section). Gen may be used in a completely analogous way to specify an alternate density fitting

basis set (see the examples). The GenECP variation may be used to read in both basis functions and ECPs; it is equivalent to Gen Pseudo=Read. It is designed for use in ONIOM calculations in which you want to use a general basis set with ECPs within one ONIOM layer. The GFPrint keyword may be used to include the gaussian function table within the output file. The GFInput keyword may be used to have the table printed in a form which is suitable for input to Gen. The ExtraBasis keyword may be used to make additions to standard basis sets. Similarly, the ExtraDensityBasis keyword may be used to make additions to standard density fitting basis sets BASIS FUNCTION OVERVIEW

A single basis function is composed of one or more primitive gaussian functions . For example, an s-type basis function φμ(r) is:

N is the number of primitive functions composing the basis function, and it is called the degree-of-contraction of the basis function. The coefficients d ιμ are called contraction coefficients. The quantities αιμ are the exponents, and f is the scale factor for the basis function. The maximum degree-of-contraction permitted in Gaussian is 100. A shell is a set of basis functions φ μ with shared exponents. Gaussian supports shells of arbitrary angular momentum: s, p, d, f, g, h, and so on. An s-shell contains a single s-type basis function. A p-shell contains the three basis functions pX, pY, and pZ. An sp-shell contains four basis functions with common gaussian exponents: one s-type function and the three p-functions pX, pY and pZ. A d-shell may be defined to contain either the six second-order functions (dX2, dY2, dZ2, dXY, dXZ, dYZ), or the five "pure d" basis functions (d z2-r 2, dx2-y2, dxy, dxz, dyz). Likewise, an fshell may contain either the 10 third-order gaussians or the 7 "pure f" functions. Higher order shells function similarly. Note that the contraction coefficients in a shell must be the same for all functions of a given angular momentum, but that s and p contraction coefficients can be different in an sp-shell. A scale factor is also defined for each shell. It


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is used to scale all the exponents of primitives in the shell. The program has the ability to convert between the two types of functions [391]. Consider the series of basis sets STO-3G, 6-31G, and 6-311G(d) for the carbon atom. With the STO-3G, basis there are two shells on a carbon atom. One is an s-shell composed of other 3 primitive gaussian functions (which least-squares fit 2s to and a Slater 1s orbital). The sp-shell is a least-squares fit of 3are gaussians to Slater 2p orbitals with the constraint that the s and p functions have equal exponents. These expansions are the same for all atoms. Only the scale factors for each shell differ from atom to atom. For carbon atoms, the 1s- and 2sp-shells have scale factors of 5.67 and 1.72, respectively. The 6-31G basis on a first row atom has three shells. One shell is a contraction of six primitive s-type gaussians. The second shell is a combination of three primitive sp-shells. The third shell consists of a single sp-function. These functions were optimized for the atom. Scale factors of 1.00, 1.00, and 1.04, respectively, for each shell for carbon were then determined by molecular calculations. As its name implies, the 6-311G(d) basis has 5 shells: an s-shell with 6 primitives, 3 sp-shells with 3, 1, and 1 primitives, and an uncontracted d-shell. All shells are "unscaled" (have unit scale factor). BASIS SET INPUT FORMAT

External basis sets are read into Gaussian by specifying Gen (for general basis) in the route section. The keywords 5D, 6D, 7F, and 10F are used to specify use of Cartesian or pure d and f (and higher) functions; the defaults are 5D and 7F. All d-shells in a calculation must have the same number of functions. Similarly, f- and higher shells must either be all Cartesian or all pure. Defining a shell. External basis input is handled

by the routine GenBas in Link 301. The

basic unit block of information that it reads fromtogether the basiswith set the input section is the shell of pure definition . A shell definition block, global specification vs. Cartesian functions, contains all necessary information to define a shell of functions. It consists of a shell descriptor line, and one or more primitive gaussian lines: IType NGauss Sc α1 d 1μ α2 d 2μ

... α N d Nμ

Shell descriptor line: shell type, # primitive gaussians, and scale factor. Primitive gaussian specification: exponent and contraction coefficient. There are a total of NGauss primitive gaussian lines.

IType defines the shell type and shell constraint and may be S, P, D, SP, SPD, F, G, ..., NGauss for an s-shell, p-shell,gaussian d-shell, shells sp-shell, and so on. number of primitive (thef-shell, degreeg-shell, of contraction) for the shellspecifies being the defined. The shell scale factor is given by Sc (i.e., all primitive exponents are scaled by Sc2).

The subsequent NGauss primitive gaussian lines define the exponents αk and contraction coefficients, dkμ. Each line provides the exponent for one primitive, followed by its contraction coefficient (or s and p coefficients for an sp-shell).


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A second format also exists to specify a shell as a least-squares gaussian expansion of a Slater orbital. This is requested by a shell descriptor line of the form STO, IOrb, NGauss, Sc. IOrb is one of 1S, 2S, 2P, 2SP, 3S, 3P, 3SP, 3D, 4SP , and specifies which expansion is requested. Note that 2SP requests the best least-squares fit simultaneously to S and P slater orbitals and is not equivalent to separately specifying the best S and the best P expansions. theavailable. same as above. Gaussian expansions of Slater functionsofhaving from 1 to 6 NGauss primitivesisare Sc is the scale factor and hence the exponent the slater function being expanded. No primitive gaussian lines are required after a shell descriptor line requesting an STO expansion. Defining the basis for an atom or atom type. One customarily places at least one, and

often several, shells on any given nuclear center ("atom"), via a center definition block . A center definition block consists of a center identifier line, and one shell definition block for each shell desired on the center(s) specified. It is terminated by a line with either asterisks or plus signs in columns 1 through 4: c2 ... 0NGauss Sc c1 IType α2 d 2μ

... α N d Nμ ...

IType NGauss Sc α2 d 2μ

... α N d Nμ ****

Center line: specifies applicability for these shells. Firstidentifier shell definition block.

Additional shell definition blocks. Final shell definition block.

Separator: terminates the center definition block.

The center identifier line specifies a list of centers on which to place the basis functions in the center definition block, by aatom(s) 0. It canincontain one or specification; more integers,more which are used to indicate the terminated corresponding the molecule commonly, it contains a list of atomic symbols to refer to all atoms of a specific type. Center numbers and atomic symbols may be freely intermixed within a single center identifier line. To help detect input mistakes, if a center definition block specifies an atom that is not present in the molecule, the run is aborted. If the center is preceded by a minus sign (e.g. -H), the basis set information is simply skipped if no atom of that type is present in the molecule specification (the terminal zero may also be omitted in this case). The latter syntax is intended for creating basis set include files that specify a standard basis set for many set atoms; once built, it can be included in its entirety in the earlier input stream the basis is desired, via the include (@) function (as described in this when chapter). A center or atom type may be specified in more than one center definition block. For example, in the Gaussian 03 basis set directory— $g03root/g03/basis on UNIX systems —there is one file which specifies 6-31G as a general basis set (631.gbs), and another file containing d exponents which would be included as well to specify 6-31G* (631s.gbs). Every atom from H through Cl is specified in both files, and in practice both of them


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would be included (most often along with additional basis set specifications for those atoms in the molecule for which the 6-31G basis set is not available). Drawing on Pre-Defined Basis Sets in Gen Input . Gaussian adds flexibility to general

basis set input by allowing them to include pre-defined basis sets within them. Within a center definition for an the atom type (orkeyword types), an shell definition block may be replaced by a lineblock containing standard forentire a pre-defined basis set. In this case, all of the functions within the specified basis set corresponding to the specified atom type(s) will be used for all such atoms within the molecule. The SDD, SHF, SDF, MHF, MDF, MWB forms may be used to specify Stuttgart/Dresden basis sets/potentials within Gen basis input. Note that the number of core electrons must be specified.

Here is a portion of the Gen input corresponding to the 6-31+G(d) basis set: H 0 S 3 1.00 0.1873113696D+02 0.3349460434D-01 0.2825394365D+01 0.2347269535D+00 0.6401216923D+00 0.8137573262D+00 S 1 1.00 0.1612777588D+00 0.1000000000D+01 **** C 0 S 6 1.00 0.3047524880D+04 0.1834737130D-02 0.4573695180D+03 0.1403732280D-01 0.1039486850D+03 0.6884262220D-01 0.2921015530D+02 0.2321844430D+00 0.9286662960D+01 0.4679413480D+00 0.3163926960D+01 0.3623119850D+00 SP 3 1.00 0.7868272350D+01 -0.1193324200D+00 0.1881288540D+01 -0.1608541520D+00 0.5442492580D+00 0.1143456440D+01 SP 1 1.00 0.1687144782D+00 0.1000000000D+01 D 1 1.00 0.8000000000D+00 0.1000000000D+01 **** C 0 Applies to all carbons. SP 1 1.00 0.4380000000D-01 0.1000000000D+01 ****

Applies to all hydrogen atoms.

Applies to all carbons. 6-31G functions.

0.6899906660D-01 0.3164239610D+00 0.7443082910D+00 0.1000000000D+01 Polarization function.

Diffuse function. 0.1000000000D+01

The following Gen input uses the 6-31G(d,p) basis set for the carbon and hydrogen atoms and the 6-31G†† basis set for the fluorine atoms in the molecule, and places an


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extra function only on center number 1 (which happens to be the first carbon atom in the molecule specification for 1,1-difluoroethylene): C H 0 6-31G(d,p) **** F 0 6-31G(d',p') **** 1 0 SP 1 1.00 0.4380000000D-01 ****

Place a diffuse function on just one carbon atom. 0.1000000000D+01

0.1000000000D+01

The following job uses the Gaussian include file mechanism to specify the basis functions for chromium: # Becke3LYP/Gen Opt Test HF/6-31G(*) Opt of Cr(CO)6

molecule specification C O 0 6-31G(d) **** @/home/gwtrucks/basis/chrome.gbs/N

Note that .gbs is the conventional extension for basis set files (for gaussian basis set ). The following example uses general basis set input to specify both the basis set and the density fitting basis set. # RBLYP/GEN/GEN 6D HCl: reading in 6-31g* AO basis and DGA1 fitting set. 6D is specified because the default for general basis input is 5D but the 6-31g* basis is defined to use 6D 0,1 cl h,1,1.29 ! here are the 6-31g* basis sets for Cl and H cl 0 S 6 1.00 0.2518010000D+05 0.1832959848D-02 0.3780350000D+04 0.1403419883D-01 0.8604740000D+03 0.6909739426D-01 0.2421450000D+03 0.2374519803D+00 0.7733490000D+02 0.4830339599D+00 0.2624700000D+02 0.3398559718D+00


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SP

SP

SP D

6 1.00 0.4917650000D+03 0.1169840000D+03 0.3741530000D+02 0.1378340000D+02 0.5452150000D+01 0.2225880000D+01 3 1.00 0.3186490000D+01 0.1144270000D+01 0.4203770000D+00 1 1.00 0.1426570000D+00 1 1.00 0.7500000000D+00

**** h 0 S 3 1.00 0.1873113696D+02 0.2825394365D+01 S

0.6401216923D+00 1 1.00 0.1612777588D+00

-0.2297391417D-02 -0.3071371894D-01 -0.1125280694D+00 0.4501632776D-01 0.5893533634D+00 0.4652062868D+00

0.3989400879D-02 0.3031770668D-01 0.1298800286D+00 0.3279510723D+00 0.4535271000D+00 0.2521540556D+00

-0.2518280280D+00 -0.1429931472D-01 0.6158925141D-01 0.3235723331D+00 0.1060184328D+01 0.7435077653D+00 0.1000000000D+01

0.1000000000D+01

0.1000000000D+01

0.3349460434D-01 0.2347269535D+00 0.8137573261D+00 0.1000000000D+01

**** ! here are the DGA1 fitting sets for Cl and H cl 0 S 1 1.00 0.2048000000D+05 0.1000000000D+01 S 1 1.00 0.4096000000D+04 0.1000000000D+01 S 1 1.00 0.1024000000D+04 0.1000000000D+01 S S

10.2560000000D+03 1.00 1 1.00 0.6400000000D+02 SPD 1 1.00 0.2000000000D+02 0.1000000000D+01 SPD 1 1.00 0.4000000000D+01 0.1000000000D+01 SPD 1 1.00 0.1000000000D+01 0.1000000000D+01 SPD 1 1.00 0.2500000000D+00 0.1000000000D+01 **** h 0 S 1 1.00 0.4500000000D+02 S 1 1.00 0.7500000000D+01 S 1 1.00 0.1500000000D+01

0.1000000000D+01 0.1000000000D+01 0.1000000000D+01

0.1000000000D+01

0.1000000000D+01

0.1000000000D+01

0.1000000000D+01

0.1000000000D+01

0.1000000000D+01

0.1000000000D+01

0.1000000000D+01 0.1000000000D+01 0.1000000000D+01


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S

1 1.00 0.3000000000D+00

0.1000000000D+01

****

If you wanted to specify the density fitting basis set with general basis set input, then you would use a route section like this one (substituting the appropriate basis set for your problem): # RBLYP/6-31G(d,p)/Gen 6D

ExtraBasis, ExtraDensityBasis , GFInput, GFPrint, Pseudo

Geom The Geom keyword specifies the source of the molecule specification input. By default, it is read from the input stream, as described previously. Geom may be used to specify an alternate input source. It also controls what geometry-related information is printed and use of internal consistency checks on the Z-matrix. The Geom keyword is not meaningful without at least one item selection option. ITEM SELECTION OPTIONS Checkpoint

Causes the molecule specification (including variables) to be taken from the checkpoint file. Only the charge and multiplicity are read from the input stream. For example, Geom=Checkpoint may be used by a later job step to retrieve the geometry optimized during an earlier job step from the checkpoint file. This action is safe since Gaussian will abort the job if an optimization fails, and consequently subsequent job steps which expect to use the optimized geometry will not be executed. May be combined with the ModRedundant option if you want to retrieve and alter the molecule specification in a checkpoint file using redundant internal coordinate-style modifications. AllCheck

Causes the molecule specification (including variables), the charge and multiplicity, and the title section to be taken from the checkpoint file. Thus, only the route section and any input required by keywords within it need be specified when using this option. This option is not valid with Modify but may be combined with ModRed. Step= N

Retrieves the structure produced by the N th step of a failed or partial geometry optimization (it is not valid for a successful optimization). Step=Original recovers the


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initial starting geometry. This option is used for restarting geometry optimization from intermediate points. It must be combined with one of Checkpoint, AllCheck or Modify. Note that not all steps are always present in the checkpoint file; a Hessian updated message in the log file means that the corresponding step is available in the checkpoint file. ModRedundant

Modify the current geometry (regardless of its coordinate system) using redundant internal coordinate modifications before performing the calculation. This option may be used to modify a geometry specified in the input file using these features even when some calculation type other than an optimization is to be performed. It may also be combined with Step, Check or AllCheck to retrieve and modify a geometry from a checkpoint file. The ModLargeRedundant variation uses the minimal setup for Opt=Large. It may not be used for periodic boundary calculations. When used with Check or Step, two input sections will be read: the first contains the charge and multiplicity, and the second contains alterations to the retrieved geometry. When combined with the AllCheck option, only the geometry modifications input is needed. Modification specifications for redundant coordinates have the same format as the input for the ModRedundant option of the Opt keyword (we summarize these formats only briefly here; see the discussion of the Opt keyword for a full description): [Type] N1 [N2 [N3 [N4]]] [[+=]Value] [ Action [ Params]] [[Min] Max]] N 1, N 2, N 3 and N 4 are atom numbers or wildcards. (numbering begins at 1 and any dummy atoms are not counted.) Value gives a new value for the specified coordinate, and +=Value increments the coordinate by Value. Action is an optional one-character code letter indicating the coordinate modification to

be performed, sometimes followed by additional required parameters (the default action is to add the specified coordinate): • •

• • •

•

B K

Add the coordinate and build all related coordinates. Remove the coordinate and kill all related coordinates containing this

coordinate. A Activate the coordinate for optimization if it has been frozen. F Freeze the coordinate in the optimization. R Remove the coordinate from the definition list (but not the related coordinates). S n stp Perform a relaxed potential energy surface scan. Set the initial value to Value (or its current value), and increment the coordinate by stp a total of n times, performing an optimization from each resulting starting geometry.


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• •

H dv Change the diagonal element for this coord. in the initial Hessian to dv. D Calculate numerical second derivatives for the row and column of the initial

Hessian for this coordinate. An asterisk (*) in the place of an atom number indicates a wildcard. Min and Max define awildcards. range (or The maximum if Min forthe coordinate specifications containing Action value is taken onlyisifnot thegiven) value of coordinate is in the range. Type can be used to designate a specific coordinate type (by default, the coordinate type

is determined automatically from the number of atoms specified): •

• • • •

•

Cartesian coordinates. In this case, Value, Min and Max are each triples of numbers, specifying the X,Y,Z coordinates. B Bond length A Valence angle D Dihedral angle X

-1) or by four atoms, where Linearatom bendisspecified by three atoms (or if N 4 is directions the fourth used to determine the 2 orthogonal of the linear bend. In this case, Value, Min and Max are each pairs of numbers, specifying the two orthogonal bending components. O Out-of-plane bending coordinate for a center ( N 1) and three connected atoms. L

Modify

Specifies that the geometry is to be taken from the checkpoint file and that modifications will be made to it. A total of two input sections will be read: the first contains the charge and multiplicity, and the second contains alterations to the retrieved geometry. Note that in Gaussian 03, Modi is the shortest valid abbreviation for this keyword. Modification specifications for geometry optimizations using Z-matrix coordinates have the following form: variable [new-value] [A|F|D] where variable is the name of a variable in the molecule specification, new-value is an optional new value to be assigned to it, and the final item is a one-letter code indicating whether the variable is to be active (i.e., optimized) or frozen; the code letter D requests numerical differentiation be performed with respect to that variable and activates the variable automatically. If the code letter is omitted, then the variable's status remains the same as it was in the original molecule specification. Connect

Specify explicit atom bonding data via an additional input section (blank line-terminated) following the geometry specification and any modification to it. This option requires one line of input per atom, ordered the same as in the molecule specification, using the following syntax: N 1 Order 1 [ N 2 Order 2 …]


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where the N 's are atoms to which the current atom is bonded, and the Order's are the bond order of the corresponding bond. For example, this input specifies that the current atom is bonded to atoms 4 and 5, with bond orders of 1.0 and 2.0 respectively: 8 4 1.0 5 2.0 -1.0 This input section is terminated by a blank line. ModConnect

Modify the connectivity of the atoms in the molecule specification (or retrieved from the checkpoint file). This option requires an additional input section (blank line-terminated) following the geometry specification and any modification to it. Connectivity modifications use the following syntax: M N 1 Order 1 [ N 2 Order 2 …]

where is the the N 's are atoms tobond. which and thea Order'sM are the atom bond number, order of the corresponding A that bondatom orderisofbonded, -1.0 removes bond. For example, this input specifies that atom 8 is bonded to atoms 4 and 5, with bond orders of 1.0 and 2.0 respectively, and removes any bond to atom 9: 8 4 1.0 5 2.0 9 -1.0 ZMConnect

Read connectivity using the atom numbering specified in the Z-matrix (including dummy atoms). Bond orders involving dummy atoms are discarded. IHarmonic=n

Add harmonic constraints to the initial structure with force constant n/1000 Hartree/Bohr 2. InitialHarmonic is a synonym for this option. ChkHarmonic=n

Add harmonic constraints to the initial structure saved on the checkpoint file with force constant n/1000 Hartree/Bohr 2. CHarmonic is a synonym for this option. ReadHarmonic=n

Add harmonic constraints to an additional structure read in the input stream (in the input 2

orientation), with force constant n/1000 Hartree/Bohr . RHarmonic is a synonym for this option. OldRedundant

Use the Gaussian 94 redundant internal coordinate generator. OUTPUT-RELATED OPTIONS


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Distance

Requests printing of the atomic distance matrix (which is the default for molecules with fewer than 50 atoms). NoDistance suppresses this output. Angle

Requests printing of the isinteratomic Z-matrix to determine which atoms are bonded. The default not to printangles, unlessusing somethe atoms are specified by Cartesian coordinates or an optimization in redundant internal coordinates is being performed. NoAngle suppresses this output. CAngle

Requests printing of interatomic angles using distance cutoffs to determine bonded atoms. The default is not to print unless at least one atom is specified using Cartesian coordinates. Only one of Angle, CAngle, and NoAngle may be specified. Dihedral

Specifies printing ofare dihedral angles using connectivity information fromsuppresses the Z-matrix decide which atoms bonded (the default is not to print). thisto NoDihedral output. CDihedral

Requests printing of dihedral angles using distance cutoffs to determine connectivity. Only one of Dihedral, CDihedral, and NoDihedral may be specified. PrintInputOrient

Include the table giving the Cartesian coordinates in the input orientation. GEOMETRY SPECIFICATION AND CHECKING OPTIONS KeepConstants KeepConstants

retains and NoKeepConstants discards information about frozen variables. The default is to retain them in symbolic form for the Berny algorithm, and to discard them for older optimization algorithms (which don't understand them anyway). KeepDefinition

Retains the definition of the redundant internal coordinates (the default). Its opposite is NewDefinition . NewRedundant

Rebuilds the redundant internal coordinates from the current Cartesian coordinates. If used with Geom=Modify, the new modifications are appended to any earlier Opt=ModRedundant input before the coordinate system is updated. Crowd Crowd activates and NoCrowd turns off a check which aborts the job if atoms are closer


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than 0.5 Å. By default, the check is done at the initial point, but not at later points of an optimization. Independent Independent

activates and NoIndependent turns off a check on the linear independence

of the variables specified in aalgorithm Z-matrix.(Opt=Z-matrix This is done by).default only if a full optimization is requested using the Berny MODEL BUILDER OPTIONS ModelA, ModelB

These options specify that model builder [500] connectivity information will be read and used to construct a symbolic Z-matrix. This option is implemented only for H through Ne, and in some cases will not generate a symbolic Z-matrix with the correct symmetryconstrained number of variables. If geometry optimization has been requested and this problem occurs, the job will be aborted. Print

Turns on additional printing by the model builder facility.

Guess=Read, Opt=ModRedundant

GFInput The GFInput ("Gaussian Function Input") output generation keyword causes the current basis set to be printed in a form suitable for use as general basis set input, and can thus be used in adding to or modifying standard basis sets.

Gen, GFPrint

GFPrint


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This output generation keyword prints the current basis set and density fitting basis set in tabular form. The variant GFOldPrint keyword prints the basis set information in the Gaussian format.

Gen, GFInput

Guess This keyword controls the initial guess for the Hartree-Fock wavefunction. Guess is not meaningful without an option. By default, a Harris guess is used (see below).

Harris

Diagonalize the Harris functional [501] for the initial guess. This is the default unless atoms heavier than Xe are present. Huckel

Requests that a Huckel guess be generated, which is the default when atoms heavier than Xe are present. RdScale

Read in the scale factor on atomic hardnesses used in iterative extended Huckel. The default is 7.0 times the QEq value. OldHuckel

Use the old Huckel guess (pre-Gaussian 03) instead of CNDO or the updated Huckel. INDO

Use the Gaussian 98 default guess: INDO for first-row systems, CNDO for secondrow,and Huckel for third-row and beyond. AM1

Do an AM1 calculation for the initial guess (currently only works with sparse matrix code). Guess=(AM1,Always) causes later steps in a geometry optimization to generate a new guess at each point and compare the energies with the density from the old point and the new guess and take the better.


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Core

Requests that the core Hamiltonian be diagonalized to form the initial guess. Guess=Core is most commonly used for atomic calculations. DensityMix [= N ]

Whether todefaults mix occupied andHuckel virtual eigenvalues orbital contributions forming the initial guess density. N to -3 (use to decideinwhich orbitals to mix). Permute

Read in a permutation of orbitals in the initial guess. The numbers of the generated guess orbitals are given in the order in which they should be used in the SCF. Ranges (e.g. 712) can be used, and all orbitals not listed are put in after the listed orbitals in their original order. Separate permutation lists for α and β orbitals must be specified (on separate lines) for open shell systems. Alter

Indicates orbitals selected for Normally, occupationthe in the Hartree-Fock should notthat be the those of lowest energy. occupied orbitals wavefunction are selected as those with lowest eigenvalues for the one-electron Hamiltonian used in the initial guess programs. The alteration sections consist of a set of transpositions indicating that one of these occupied orbitals is to be replaced by one of the other (virtual) orbitals. Each such transposition is on a separate line and has two integers N 1 and N 2 (free format, separated by spaces or a comma as usual) indicating that orbital N 1 is to be swapped with orbital N 2. The list of orbital transpositions is terminated by the blank line at the end of the input section. For UHF calculations, two such orbital alteration sections are required, the first specifying transpositions orbitals, and the second of β orbitals. Both sections areofα always required. Thus, evenspecifying if only α transpositions are needed, the β section is required even though it is empty (and vice-versa). The second blank line to indicate an empty β section must be included. Read

Requests that the initial guess be read from the checkpoint file (Guess=Read is often specified along with Geom=Checkpoint). This option may be combined with Alter, in which case the orbitals are read from the checkpoint file, projected onto the current basis set, and then the specified alterations are made. Checkpoint is a synonym for Read. The TCheck option says to attempt to read a guess from the checkpoint file, but to generate a new one if necessary. Always

Requests that a new initial guess be generated at each point of an optimization. By default, the SCF results from the last point are used for the guess at the next point.


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Mix

Requests that the HOMO and LUMO be mixed so as to destroy α-β and spatial symmetries. This is useful in producing UHF wavefunctions for singlet states. LowSymm

Requests irreducible representations point lowered group besymmetry combinedofinthe the symmetrythat information used in the N 3 stepsofinthethemolecular SCF, to allow wavefunction. This enables the orbitals (and possibly but not necessarily the total wavefunction) to have lower symmetry than the full molecular point group. This option is available only for GVB calculations, where it is often necessary for calculations on symmetric systems (see the discussion of the GVB keyword below for an example using this option). The option expects a single line of input (in the format 16I2) giving the numbers of the irreducible representations to combine, with the new groups separated by 0; the list itself must be terminated by a 9. The numbers correspond to the order in which the representations are listed by Link 301 in the output file (see the examples subsection below). Since this input section is always exactly one line long, it is not terminated by a blank line. Note that irreducible representations are combined before orbital localization is done and that localized orbitals retain whatever symmetry is kept. Guess=NoSymm removes all orbital symmetry constraints without reading any input. NoSymm

Requests that all orbital symmetry constraints be lifted. Synonymous with SCF=NoSymm and Symm=NoSCF. Local

Requests that orbitals be localized using the Boys method [421]. Occupied and virtual orbitals are localized separately, and the irreducible representations (after possible merging using LowSymm or NoSymm) are not mixed. Localized orbital analysis of a converged SCF wavefunction may then be done using a second job step, which includes Guess(Read,Local,Only ) and Pop=Full in its route section. Translate Translate

requests that the coordinates of the atoms used to produce a guess, which is read in, be translated to the current atomic coordinates. This is the default. It may fail in unusual cases, such as when a wavefunction is used as a guess for abe system with a different stoichiometry, in which case Guess=NoTranslate should specified. Cards

Specifies that after the initial guess is generated, some or all of the orbitals will be replaced with ones read from the input stream. This option can be used to read a complete initial guess from the input stream by replacing every orbital. The replacement orbitals


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are placed in the input section following the guess alteration commands, if any. For UHF, there are separate α and β replacement orbital input sections. The replacement orbitals input section (the α replacement orbitals section for UHF) begins with a line specifying the Fortran format with which to read the replacement orbital enclosed parentheses. example: (4E20.8). The remainder of the sectioninput, contains one orinmore instancesFor of the following:

IVec

( A( I,IVec ), I=1 ,N )

0=end, Orbital to replace ( -1=replace all orbitals in order). New orbital in the format specified in the first line.

The format for the line containing IVec is Fortran I5. The β orbital replacement section for UHF calculations differs only in that it omits the initial format specification line. See the examples section for sample replacement orbital input. Only Guess=Only

functions as a calculation type keyword and requests that the calculation terminate once the initial guess is computed and printed. Note that the amount of orbital information that is printed is controlled by the Pop keyword. Guess=Only may not be used with semi-empirical methods. This option is useful in preliminary runs to check if configuration alteration is necessary. For example, Guess=Only may be specified with CASSCF in order to obtain information on the number of CI configurations in the CAS active space (as well as the initial orbitals). Guess(Only,Read ) may also be used to produce population and other post-calculation

analyses from the data in a checkpoint file. For example, these options alone will produce a population analysis using the wavefunction in the checkpoint file. Guess(Only,Read ) Prop will cause electrostatic properties to be calculated using the wavefunction in the checkpoint file. Save

Save the generated initial guess back into the checkpoint file at the conclusion of a Guess=Only run. This option is useful for saving localized orbitals. Print

Print the initial guess. Alpha

Use alpha orbitals for both alpha and beta guess during Guess=Read. Fock

Reuse Fock matrices rather than orbitals when reading from previous results on the rwf or chk files. This is the default for periodic boundary conditions calculations if Guess=Alter is not specified. NoFock disables this behavior, and it is the default for non-PBC calculations.


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Extra

Do an extra, new initial guess when reading orbitals from the RWF (i.e., during geometry optimizations). By default, this is done if the default Harris guess is allowed, no alteration of configuration was requested, and the optimization did not take a small step as flagged by variable 4 in ILSW . Use NoExtra to disable this feature. ForceAbelianSymmetry

Force the initial guess orbitals to transform according to irreps of the Abelian point group. NoForceAbelianSymmetry is the default. Sparse

Perform a sparse SE calculation for the initial guess. This option may be useful for very, very large HF or DFT calculations using the sparse matrix facility. NaturalOrbitals

Include orbitals in the checkpoint file. This must be accomplished a separate job step natural specifying this option as well as Check , Only , and Read. See the via discussion of the Population keyword for details. These options may be combined in any reasonable combination. Thus Guess=(Always,Alter ) and Guess=(Read,Alter ) work as expected (in the former case, alterations are read once and the same interchanges are applied at each geometry). Conversely, Guess=(Always,Read ) is contradictory and will lead to unpredictable results. Refer to the input sections order table at the beginning of this chapter to determine the ordering of the input sections for combinations of options like Guess=(Cards,Alter ). RESTRICTIONS Guess=Only

may not be used with semi-empirical methods.

Geom, Pop

Transposing 2 Orbitals with Guess=Alter. This example finds the UHF/STO-3G structure of the 2A1 excited state of the amino radical. First, a Guess=Only calculation is

run to determine whether any alter instructions are needed to obtain the desired electronic state. The HF/STO-3G theoretical model is used by default: # Guess=Only Test Amino radical test of initial guess


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0 2 n h 1 nh h 1 nh 2 hnh nh 1.03 hnh 120.0

Here is the orbital symmetry summary output from the job, which comes immediately before the population analysis in the output: Initial guess orbital symmetries. Alpha Orbitals: Occupied (A1) (A1) (B2) (B1) (A1) Virtual (A1) (B2) Beta Orbitals: Occupied (A1) (A1) (B2) (A1) Virtual (B1) (A1) (B2) of initial guess= .7544

Since a doublet state is involved, α and β orbitals are given separately. From the orbital symmetries, the electron configuration in the initial guess is a 12a12 b22a12 b1, yielding a 2B1 wavefunction. This is indeed the ground state of NH2. The expectation value of S2 for the unrestricted initial guess is printed. In this case, it is close to the pure doublet value of 0.75. Note that the orbital energies printed in a Guess=Only job are simply -1.0 for the occupied orbitals and 0.0 for the virtual orbitals, since no SCF has been performed. If the actual orbital energies are desired, a full semi-empirical energy calculation can be performed specifying the desired method (e.g. INDO). Returning to our consideration of the amino radical, since we want to model the 2A1 excited state, we will need to alter this initial orbital configuration: a β electron must be moved from orbital 4 to orbital 5 (the electron configuration is then a12a12 b22 b12a1). Guess=Alter

may also be used to accomplish this. Here is the input for the geometry

optimization # UHF/6-31G(d) Opt Guess=Alter Pop=Reg Test Amino radical: HF/6-31G(d) structure of 2-A1 state 0 2 n h 1 nh h 1 nh 2 hnh Variables: nh 1.03 hnh 120.0

Blank line ends the molecule specification section.


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4 5

Blank line ends the α section(empty in this case). Transpose orbitals 4 and 5. End of the β alteration section.

Note that an extra blank line-line 12-is necessary to indicate an empty α alteration section. The final two lines then constitute the β alteration section. The initial guess program prints a list of orbitals that were interchanged as a result of the Alter option: Projected INDO Guess. NO ALPHA ORBITALS SWITCHED. PAIRS OF BETA ORBITALS SWITCHED: 4 5

The eigenvalue of S2 is printed for the UHF wavefunction. The value which results if contamination of the wavefunction from the next possible spin multiplicity (quartets for doublets, quintets for triplets, etc.) is removed is also printed: Annihilation of the first spin contaminant: S**2 before annihilation .7534, after

.7500

Although this calculation does in fact converge correctly to 2A1 state, it sometimes happens that the order of orbital symmetries switches during the course of the SCF iterations. If the orbital symmetries of the final wavefunction are different from those in the initial guess (whether or not you are using Guess=Alter), we recommend using the direct minimization routine, specified with the SCF=QC or SCF=DM keywords, which usually holds symmetry from one iteration to the next. This option is often is the easiest way to perform a complex modification of the initial guess, as in this example: Reordering Orbitals with Guess=Permute.

# CASSCF/6-31G(d,p) Opt Guess=Permute Pop=Reg Test CAS job 0 1

molecule specification 1-60 65 63 64 66 68 67 61-62 69

Specify new ordering.

Here we have rearranged orbitals 61-68. Listing the final orbital (69) is not really necessary, but it help to make the input easier to understand for humans. Reading in Orbitals with Guess=Cards. Some or all of the orbitals may be replaced after the initial guess is generated using Guess=Cards. Here is some sample input for

this option, which replaces orbitals 1 and 4 (note that the format for the third and following lines is specified in line 1):


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(3E20.8) 1 0.5809834509E+00 0.1724432549E-02 0.1639966912E-02 -0.4538843604E-03 0.6038992969E-04 4 0.7700779642E-13 -0.4479190461E-12 0.6441113412E-12 -0.1190754528E-11 -0.2567325943E+00 0

0.4612416518E+00 0.1282235396E-14 -0.9146282229E-15 0.6038992958E-04 -0.1131035471E-03

-0.6437319952E-04 0.5417658499E-13 -0.6407549694E-13 -0.1131035485E-03

0.1240395916E-12 -0.1478805861E-13 -0.3119296374E-14 0.2567325943E+00 -0.1459733219E+00

-0.3110890228E-12 0.5807753928E+00 0.1554735923E+00 0.1459733219E+00

An orbital number of zero ends the replacement orbital input.

GVB This method keyword requests a perfect-pairing General Valence Bond (GVB-PP) calculation. GVB requires one parameter: the number of perfect-pairing pairs to split; for example: GVB(4). This parameter may also be specified with the NPair option. The natural orbitals for the GVB pairs are taken from occupied and virtual orbitals of the initial guess determinant (described below). INPUT FOR GVB CALCULATIONS

Normally most of the difficult input for a GVB-PP calculation involves specifying the initial guess. (Link 401). This often includes alteration of orbitals to ensure the correct identification of high-spin, perfect-pairing, and closed-shell orbitals and possible reduction of SCF symmetry to account for the localized orbitals which usually represent the lowest energy solution for GVB-PP. The GVB program reads the number of orbitals in each GVB pair (in format 40I2). The number of lines read is fixed (and normally 1), so no terminating blank line is needed. For a molecule having spin multiplicity S, N GVB pairs, and n1, ..., n N orbitals in each pair, orbitals from the initial guess are used in the following manner by the GVB program: The S-1 highest occupied orbitals in the initial guess, which would have been singly occupied in an ROHF calculation, become high-spin orbitals. The next lower N occupied orbitals, which would have been doubly occupied in an ROHF calculation, become the first natural orbitals of the GVB pairs. Any remaining orbitals occupied in the guess stay closed-shell. •

•

•


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•

•

The lowest n1-1 virtual orbitals become natural orbitals 2 through n1 of the first GVB pair, then the next n2-1 orbitals are assigned to pair 2, and so on. The GVBPP scheme does not allow an orbital to be shared by more than one GVB pair. Any remaining (virtual) orbitals from the initial guess become virtual orbitals in the GVB calculation.

Generally Guess=Alter is required to ensure that guess occupied orbitals, which will be used as first natural orbitals, match up with the correct guess virtual orbitals which will become the corresponding higher natural orbitals. Often it is helpful to start off with Guess=(Local,Only ), examine the orbitals to determine alteration requirements, then do Guess=(Local,Alter ) and GVB(NPair=N,Freeze) to allow the higher natural orbitals to become more appropriate. Finally the full calculation can be run with Guess=Read and all orbitals optimized in the GVB. If there is any confusion or concern with the orbitals breaking symmetry, the calculation should be done with Symm=NoSCF and initially with Guess=Local. In fact, this approach is generally recommended except for those very expert users. If the number of orbitals in a pair is negative, the root of the CI to use for that pair and the pair's initial GVB coefficients are read in format (I2,5D15.8). This is useful if a 1Σ or 1Δ state is being represented as a GVB pair of the form x2 ± y2.

NPair

Gives the number of perfect-pairing pairs. GVB( N ) is equivalent to GVB(NPair= N ). NPair=0 is acceptable and results in a closed-shell or spin-restricted SCF calculation. InHam= N

Read in N Hamiltonians (Fock operators, sets of coupling coefficients). This option may be combined with perfect-pairing pairs. Each Hamiltonian is read using the following syntax (format in parentheses):

NO Fj ( AJ(I), I =1,NHam ) ( AK(I), I =1,NHam )

# of orbitals in current Hamiltonian (I5) Occup. # (1.0=closed-shell) (D15.8) J coefficients (5D15.8) K coefficients (5D15.8)

Combining several orbitals with the same AJ and AK coefficients into one "shell" is not currently supported, so NO is always 1. The ham506 utility can be used to generate averaged Hamiltonians for the common case of spherical averaging in atomic calculations. The Hamiltonian coefficients are described in Bobrowicz and Goddard [105]. A good introduction to the qualitative interpretation of GVB wavefunctions can be found in the review article by Goddard and Harding [502].


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OSS

Do a two electron, two orthogonal orbital open-shell singlet. This option may be combined with perfect-pairing pairs. OpenShellSinglet is a synonym for OSS. Freeze

Freeze closed-shell andhigher open-shell orbitals, andThis firstoption naturalis orbitals of starting GVB pairs, allowing only 2nd and orbitals to vary. useful for off difficult wavefunctions.

Energies, analytic gradients, and numerical frequencies.

Here is a GVB(3/6) calculation performed on singlet methylene: # GVB(3)/6-31G(d) Guess=(Local,LowSym,Alter) Pop=Full Test GVB(3) on CH2

molecule specification 1 4 0 2 3 9 2,3 2 2 2

Guess=LowSym input Guess=Alter input GVB input

Each of the 3 valence electron pairs is split into a GVB pair. A preliminary Guess=Only

calculation was performed to determine the localized orbitals and what alterations would be required.

The perfect pairing GVB method includes the effects of intra-pair correlation but not those of inter -pair correlation. Consequently, GVB electrons pairs tend to be localized. In the case of singlet methylene, the carbon lone pair is localized even at the Hartree-Fock level. The canonical Hartree-Fock orbitals for the C-H bonds are delocalized into linear combinations (C-H1 + C-H2) and (C-H1 - C-H2) having A1 and B2 symmetry, respectively. In order to allow the localization in the guess to produce separate bond pairs, these two irreducible representations must be combined. Similarly, the GVB calculation itself must betotold to imposeCombining the full molecular symmetry on the orbitals, which would force them be not delocalized. the A1 and B2 representations and combining the A2 and B1 representations causes the calculation to impose only C s symmetry on the individual orbitals, allowing separate GVB pairs for each bond. Since the resulting pairs for each bond will be equivalent, the resulting overall wavefunction and density will still have C2v symmetry.


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The Guess=LowSym keyword specifies that the irreducible representations of the molecular point group will be combined in the symmetry information used in a GVB calculation. It takes a single line of input consisting of giving the numbers of the irreducible representations to combine, where the numbers correspond to the order in which the representations are listed in the output file (they appear just after the standard orientation). For example, here is the output for a molecule with C2v symmetry: There There There There

are are are are

4 0 1 2

symmetry symmetry symmetry symmetry

adapted adapted adapted adapted

basis basis basis basis

functions functions functions functions

of of of of

A1 A2 B1 B2

symmetry. symmetry. symmetry. symmetry.

Thus for C2v symmetry, the order is A1, A2, B1, B2, referred to in the Guess=LowSym input as 1 through 4, respectively. A zero separates groups of representations to be combined, and a nine ends the list. Thus, to combine A1 with B2 and A2 with B1, thereby lowering the SCF symmetry to Cs, the appropriate input line is: 1 4 0 2 3 9

Since this information always requires exactly one line, no blank line terminates this section. The order of orbitals generated after localization by the initial guess in the first job step was C-1s C-H1 C-H2 C-2s for the occupied orbitals, and C-2p C-H1* C-H2* for the lowest virtual orbitals. Hence if no orbitals are interchanged, the C-2s lone pair would be correctly paired with the unoccupied p-orbital, but then the next lower occupied, C-H2, would be paired with the next higher virtual, C-H1*. So either the two bond occupied orbitals or the two bond virtual orbitals must be exchanged to match up the orbitals properly. Finally, the one line of input to the GVB code indicates that there are 2 natural orbitals in each of the 3 GVB pairs.

HF This method keyword requests a Hartree-Fock calculation. Unless explicitly specified, RHF is used for singlets and UHF for higher multiplicities. In the latter case, separate α and β orbitals will be computed [57,58,59]. RHF, ROHF or UHF can also be specified explicitly. SCF single point energy calculations involving basis sets which include diffuse functions should use the SCF=Tight keyword to request tight SCF convergence criteria.


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Energies, analytic gradients, and analytic frequencies for RHF and UHF and numerical frequencies for ROHF.

The Hartree-Fock energy appears in the output as follows: SCF Done: E(RHF) = Convg = S**2 =

-74.9646569691 .6164D-03 .0000

A.U. after 4 cycles -V/T = 2.0063

The second and third lines give the SCF convergence limit and the expectation value of S2.

Huckel This method keyword requests an extended Hückel calculation [503,504,505,506,507]. ExtendedHuckel is a synonym for this keyword. No basis set keyword should be specified.

Hoffmann

Requests an Extended Huckel calculation using the default parameter set from the Huckel group. Muller

Requests an Extended Huckel calculation using parameters collected by Edgar Muller. Guess

Requests an Extended Huckel calculation using the modified parameters used for Guess=Huckel [508,509,510].

Energies, "analytic" gradients and numerical frequencies.


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The energy appears in the output file as follows (followed by the x, y, and z components of the dipole moment): Huckel eigenvalues -- -1.245 -0.637 -0.558 -0.544 -0.043 Energy= -5.968836513622 NIter= 0. Dipole moment= 0.000000 0.000000 0.000000

0.352


Guess=Huckel

INDO Requests a semi-empirical calculation using the INDO Hamiltonian [42]. No basis set keyword should be specified.


The INDO energy appears in the output file as follows (followed by the x, y, and z components of the dipole moment): Energy= -19.034965532835 NIter= 10. Dipole moment= .000000 .000000 -.739540


Integral


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The Integral keyword modifies the method of computation and use of two-electron integrals and their derivatives. INTEGRATION GRID SELECTION OPTION Grid= grid

Specifies the integration grid to be used for numerical integrations. Note that it is very important to use the same grid for all calculations where you intend to compare energies (e.g., computing energy differences, heats of formation, and so on). The parameter to this option is either a grid name keyword or a specific grid specification. If a keyword is chosen, then the option name itself may be optionally omitted (i.e, Integral(Grid=FineGrid ) and Integral(FineGrid ) are equivalent). "Pruned" grids are grids that have been optimized to use the minimal number of points required to achieve a given level of accuracy. Pruned grids are used by default when available (currently defined for H through Kr). The default grid is a pruned (75,302) grid, having 75 radial shells and 302 angular points per shell, resulting in about 7000 points per atom; the value FineGrid is used to specify this grid. Other grids may be selected by giving an integer value N as the argument to Grid. requests a pruned (99,590) grid. It is recommended for molecules containing lots of tetrahedral centers and for computing very low frequency modes of systems. Grid=UltraFine

Other special values for this parameter are CoarseGrid, which requests a pruned version of the (35,110) grid, and SG1Grid , a pruned accuracy version ofand (50,194). Note, however,than thatthese the FineGrid has considerably better numerical rotational invariance grids, and they are not recommended for production calculations [511]. Pass0Grid requests the obsolete pruned (35,110) grid once intended for pass 0 of a tight SCF calculation. Specific grids may be selected by giving an integer value N as the argument to Grid. N may have one of these forms: •

•

A large positive integer of the form mmmnnn, which requests a grid with mmm radial shells around each atom, and nnn angular points in each shell. The total mmm*nnn number of integration points per atom is). thus . Forofexample, specify the (99,302) grid, use Int(Grid=99302 The valid numbers angular to points are 38, 50 [512], 72 [513], 86, 110 [512], 146, 194, 302 [514], 434 [515], 590, 770, and 974 [516]. If a larger number of angular points is desired, a spherical product grid can be used. A large negative integer of the form -mmmnnn, which requests mmm radial shells around each atom, and a spherical product grid having nnn θ points and 2*nnn φ points in each shell. The total number of integration points per atom is therefore


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•

2*mmm*nnn2. This form is used to specify the (96,32,64) grid commonly cited in benchmark calculations: Int(Grid=-96032 ). Note, that any value for nnn is permitted, although small values are silly (values of nnn < 15 produce grids of similar size and inferior performance to the special angular grids requested by the second format above). Large values are expensive. For example, a value of 200100 would use 2*200*100*100 or 4 million points per atom!

RELATIVISTIC CALCULATIONS DKH

Requests a Douglas-Kroll-Hess 2nd order scalar relativistic calculation [517,518,519,520] (see [521,522] for an overview). This method uses a Gaussian nuclear model [523]. DKH2 and DouglasKrollHess are synonyms. NoDKH and NonRelativistic

request a non-relativistic core Hamiltonian, which is the

default. DKH0

Requests a Douglas-Kroll-Hess 0th order scalar relativistic calculation RESC

Requests a RESC scalar relativistic calculation INTEGRAL FORMAT OPTION Raff Raff requests that the Raffenetti format for the two-electron integrals be used. This is the default. NoRaff demands that the regular integral format be used. It also suppresses the

use of Raffenetti integrals during direct CPHF. This affects conventional SCF and both conventional and direct frequency calculations. CNDO

Do calculation in main code using CNDO/2 ints. INDO

Do calculation in main code using INDO/2 ints. ZINDO1

Do calculation in main code using ZINDO/1 ints. ZINDOS

Do calculation in main code using ZINDO/S ints. ALGORITHM SELECTION OPTIONS


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SSWeights

Use the weighting scheme of Scuseria and Stratmann [524] for the numerical integration for DFT calculations. This is the default. BWeights

Use the weighting scheme of Becke for numerical integration. NoSComp

Turn off symmetry blocking of MO 2-electron integrals. NoSymmComp is a synonym for NoSComp. DPRISM

Use the PRISM algorithm [27] for spdf integral derivatives. This is the default. Rys1E

Evaluate one-electron integrals using the Rys method [525,526,527], instead of the default method. This is necessary on machines with very limited memory. Rys2E

If writing two-electron integrals, use Rys method (L314) [192,525,526,527]. This is slower than the default method, but may be needed for small memory machines and is chosen by default if regular (non-Rafenetti) integrals are requested (by the NoRaff option). Berny

Use Berny sp integral derivative and second derivative code (L702). Pass Pass specifies that the integrals be stored in memory via disk, and NoPass disables this. Synonymous with SCF=[No]Pass, which is the recommended usage. Symm NoSymm disables and Symm enables the use of symmetry in the evaluation and storage of integrals (Symm is the default). Synonymous with the keywords Symm=[No]Int,

which is the recommended usage. NoSP

Do not use the special sp integral program (L311) when writing integrals to disk. RevDagSam

Reverse choice of diagonal sampling in Prism. CPKS1Mat

Don't use CPKS multiple-matrices code.


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SquareLoops

Forces square loops. SqLoops is a synonym for this option. NoJEngine

Forbid use of special Coulomb code. FofCou

Use FoFCou even when it would not otherwise be used. NoFoFCou forbid uses of FoFCou. RevRepFock

Reverse choice of Scat20 vs. replicated Fock matrices. NoSchwartz

Turn off Schwartz cutoffs in FMM/NFx. NoMPCut

Turn off MP-based cutoffs in FMM/NFx. NoDFTCut

Turn off extra DFT cutoffs. LTrace

Trace Linda transactions. SplitSP

Split AO S=P shells into separate S and P shells. NoSplitSP is the default. SplitSPDF

Split AO S=P=D and S=P=D=F shells into S=P, D, and F. NoSplitSPDF is the default. SplitDBFSP

Split density S=P shells into separate S and P shells. NoSplitDBFSP is the default. SplitDBFSPDF

Split density S=P=D and S=P=D=F into S=P, D, and F. NoSplitDBFSPDF is the default. NoGather

Forbid useSplatter of gather/scatter digestion, when processing small numbers of density matrices. is a synonym for thiseven option. ForceNuc

Do nuclear-electron Coulomb with electron-electron. ECPAcc= N

Set ECP accuracy parameter to N .


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NoSqrtP

Turn off use of Sqrt(P) in density-based cutoffs. SepJK

Do J and K in HF/hybrid DFT separately for testing. UnconAOBasis

Uncontract all the primitives in the AO basis. UncontractAOBasis is a synonym for this option. UnconDBF

Uncontract all the primitives in the density fitting basis. UncontractDensityBasis is a synonym for this option. NoDMRange

Do not the density matrix in assigning FMM NF/FF ranges. By default, Sqrt(P) is included in ranges when only Coulomb and not exchange is being computed. NoPCXC

Do not precomputed grid information for DFT XC quadrature. NoPreComputeXC is a synonym for this option. PCXCP

Precompute XC quadrature parameters (number of significant functions, etc.) used for allocation, but do not store information about individual grid points. PreComputeXCParameters is a synonym for this option. PCXCWt

Precompute XC quadrature parameters and store weights for each point, to save the work of recalculating the weights. PreComputeXCWeights is a synonym for this option. PCXCGrid

Precompute XC quadrature parameters and store both the weight and coordinates for each grid point. PreComputeXCGridPoints is a synonym for this option. Seq2E

Set up for parallel 2 electron integral evaluation but then do not run in parallel (for debugging). SeqXC

Set up for parallel 2 electron integral evaluation but then do not run in parallel (for debugging). BigAtoms

Make all atom sizes large in XC quadrature.


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BigShells

Make all shell sizes large in XC quadrature. NoSymAtGrid

Do not use (Abelian) symmetry to reduce grid points on symmetry-unique atoms. LinMIO

Convert to linear storage in FoFCou for testing. RevDistanceMatrix

Reverse choice of whether to precompute distance matrix during numerical quadrature. The default is to precompute for molecules but not for PBC. NoXCTest

Skip tests of numerical accuracy of XC quadrature. INTEGRAL FILE-RELATED OPTIONS ReUse

Use an existing integral file. Both the integral file and checkpoint file must have been preserved from a previous calculation. Only allowed for single point calculations and Polar=Restart. WriteD2E

Forces the integral derivative file to be written in HF frequency calculations. Useful only in debugging new derivative code. BUFFER SIZE OPTIONS IntBufSize= N

Sets the integral buffer size to N integer words. The default value (which is machinedependant) is generally adequate. D2EBufSize= N

Sets the integral derivative buffer size to N words.

SCF

IOp


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The IOp keyword allows the user to set internal options (variables in system common /IOp/ ) to specific values. The syntax is: IOp(Ov1 /Op1=N 1 ,Ov2 /Op2=N 2 , ...) i i i which option number to arbitrary the value N for every overlay Ov Since settingsets internal options canOp have effects on theoccurrence calculation,ofarchiving is .disabled by use of this keyword.

IOp values explicitly set in the route section are not passed on to the second and

subsequent automatically-generated job steps; this applies to keyword combinations like Opt Freq and to inherently multi-step methods such as G2 and the CBS methods. For example, if you want to specify an alternate grid for a DFT optimization+frequency job, you must use an option to the Int=Grid keyword rather than an explicit IOp value. The execution of each overlay of Gaussian 03 is controlled by options (numbered from 1 to 50). Each is option be assigned an integer value,ofwith 0 being the default. The value of an option held may unchanged throughout execution all of the links in one overlay. Thus the significance of a particular option applies to all the component links in one pass through the overlay. The full list of Gaussian 03 options is given in the Gaussian 03 IOps Reference . They are also documented on our web site: www.gaussian.com/iops.htm.

Overlay 1

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 88 89 90 91 92 94 95 96 97 98 101 102 103 104 105 106 107 108 109 110 111 112 113 114 Overlay 2

9 10 11 12 13 14 15 16 17 18 19 20 29 30 40 41 Overlay 3

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 67 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 Overlay 4


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5 6 7 8 9 10 11 13 14 15 16 17 18 19 20 21 22 23 24 25 26 28 29 31 33 34 35 36 37 38 43 44 45 46 47 48 60 61 62 63 64 65 66 67 68 69 71 72 80 81 82 110 Overlay 5

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 45 47 48 49 50 51 52 53 55 56 57 58 59 60 61 62 63 64 65 70 71 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 Overlay 6

15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 70 71 72 73 74 75 76 77 78 79 80 81 82 Overlay 7

6 7 8 9 10 11 12 13 14 15 16 18 25 29 30 31 32 40 41 42 43 44 45 52 53 64 65 70 71 72 74 75 76 77 87 Overlay 8

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 27 28 29 30 31 32 35 36 38 39 40 41 42 43 44 45 46 47 Overlay 9

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 25 26 27 28 30 31 36 37 38 40 41 42 43 44 45 46 47 48 49 60 61 62 70 71 72 73 74 75 81 82 83 84 85 86 Overlay 10

5 6 7 8 9 10 11 13 14 15 16 17 18 19 20 21 22 28 29 30 31 32 45 46 47 48 60 61 62 63 72 72 74 75 76 77 78 79 Overlay 11

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 26 27 28 29 30 31 32 33 39 40 41 42 43 45 46 53 60 61 62 63 70 71 75 Overlay 9999

5 6 7 8 9 10 11 12 13 14 15 16 17 18 33


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Overlay 1 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 88 89 90 91 92 94 95 96 97 98 101 102 103 104 105 106 107 108 109 110 111 112 113 114 IOp(1/5)

L103 MODE OF OPTIMIZATION 0 FIND LOCAL MINIMUM 1 FIND A SADDLE POINT N FIND A STATIONARY POINT ON THE ENERGY SURFACE WITH N NEGATIVE EIGENVALUES OF THE 2ND DERIVATIVE MATRIX L107: MODE OF SEARCH 0 LOCATE THE MAXIMUM IN THE LST PATH. 1 SCAN THE LST PATH. IOp(1/6)

L102, L103, L105, L107, L109, L112, L113, L114: MAXIMUM NUMBER OF STEPS (OR NUMBER OF STEPS FOR AN LST SCAN). 0 N

NSTEP == Min(20,NVAR+10) Max(20,NVAR+10) (L102, (L103,L105, L112)L109) = Min(40,NVar+20) (L113, L114) NSTEP = N

IOp(1/7)

L103, L105, L109, L112, L113, L114: CONVERGENCE ON THE FIRST DERIVATIVE AND ESTIMATED DISPLACEMENT FOR THE OPTIMIZATION RMS FIRST DERIVATIVE .LT. CONFV, RMS EST. DISPLACEMENT .LT. CONVX=4*CONVF -1 ConvF = 1/600 HARTREE/BOHR OR RADIAN 0 CONVF = 0.0003 HARTREE/BOHR OR RADIAN N CONVF = N*10**-6 L116, L117: Convergence on electric field/charges -1 Default value for optimizations: 10**-7. 0 Default value for single-points: 10**-5 in L116, 10**-7 in L117. N 10**-N.


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IOp(1/8)

L103, L109, L112: MAXIMUM STEP SIZE ALLOWED DURING OPT. 0 DXMAXT = 0.1 BOHR OR RADIAN (L103, Estm or UnitFC). = 0.3 Bohr or Radian (L103, Read or CalcFC). N

= = 0.2 0.3 Bohr Bohr or or Radian Radian (L105). (L113, L114). DXMAXT = 0.01 * N

L117: General control. 0 Which type of basin to use to partition the density isosurface. Default is 4 1 GradVne 2 GradRho 3 Don't Use Basins, Use only the Center of NuclearCharge 4 Use Interlocking Spheres N0 Order of Adam's-Bashforth-Moulton (ABM) predictor-corrector method to use in solving diff. eqns. of forsmall the grad or Vnestep trajectories. is 4,ABM max isand 9. when N00 Number stepsRHO per ABM to be usedDefault in starting "slow down" is needed in ABM. Default is 5. N000 Which approximation to make. Default is III for Tomasi (interlocking spheres) and IV for general surface. 1000 Apprx. I - Don't Do Self-Polarization or "Compensation" 2000 Apprx. II - Do-Self Polarization, But No Compensation. 3000 Apprx. III - Do Self-Polarization and Compensation. 4000 Apprx. IV - Do III and Allow Surface To "Relax" in Solution if no spheres N0000 Whether to evaluate densities using orbitals or density matrix. Default is to use density. 10000 20000

Use Use MOs. density.

L121: Time step, N*0.0001 fs, default 0.1 IOp(1/9)

L103: Use of Trust radius. 0 Whether to update trust radius (DXMaxT, default Yes). Default is Yes for minima, no for TS. 1

No.

2

Yes.

00 Whether to scale or search the sphere when reducing the step size to the trust radius (Default search for minima, scale for transition states.).


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10

Scale.

20

Search.

L107: WHETHER TO MAINTAIN SYMMETRY ALONG THE SEARCH PATH. 0

YES.

1

NO.

L117: Whether to delete points which are too close together: 0

No

1

Yes, using a default criteria (0.05 Angstroms)

-N search.Yes, using a (10**-N Angstroms) criteria. How close to get to the isosurface in 0

Approx 1.0D-6 (N=20) N

2.0**-N

L121: Whether to read in initial velocities: 0

Default (same as 1)

1 2

Generate random initial velocity Read in initial cartesian velocity (Bohr/sec)

3

Read in initial MW cartesian velocity (sqrt(amu)*Bohr/sec)

IOp(1/10)

L103, L105, L109, L112, L113, L114: Input of initial Hessian: All values must be in atomic units (Hartree, Bohr, and radians). 0

Use defaults (not valid for L109).

1

Read ((FC(I,J),J=1,I),I=1,NVAR) (8F10.6) (L103 only).

2

Read I,J,FC(I,J), (5I3,F20.0) (L103 only). End with a blank card.

3

Read from checkpoint file in internal coordinates.


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4

Second derivative matrix calculated analytically. (not valid for L109).

5 Read cartesian forces and force constants from the checkpoint file are convert to internal coordinates. 6

Read cartesian forces followed by cartesian force constants (both in format 6F12.8) from input stream. followed by a blank line.

7

Use semiempirical force constants.

8

Use unit matrix (default for L105; only recognized by 103).

9

Estimate force constants using valence force field.

10

Use unit matrix throughout.

IOp(1/11)

L103: TEST OF CURVATURE. BOMB THE JOB IF THE SECOND SECOND DERIVATIVE MATRIX HAS THE WRONG NUMBER OF NEGATIVE EIGENVALUES. 0 DEFAULT (TEST for z-matrix or cartesian TS but not for LST/QST or for minimum). 1

DON'T TEST.

2

TEST.

L117: Scaling Factor for Determining Overlaps of VDW atoms -1

Turn off scaling

0

Default is 1.010

N

1.000 + N*(0.001)

Step size for ABM method in Trudge for isodensity method. 0 0.05 (N=2)

N

0.1/N

IOp(1/12)


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L103: OPTIMIZATION CONTROL PARAMETERS 0

USE DEFAULT VALUES

1

READ IN NEW VALUES FOR ALL PARAMETERS (SEE INITBS)

IOp(1/13)

L103,L113,L114,L115: Type of Hessian Update: 0 Default (9 for L103 minimization, 7 for L103 TS, D2Corr and L115, Powell for L113 and L114). 1

Powell (not in L103).

2

BFGS (not in L103)

3

BFGS, safeguarding positive definateness (not inL103 or L115)

4

D2Corr (New, only in L103 and L115).

5

D2Corr (Old, only in L103 and L115).

6

D2Corr (BFGS)

7

D2Corr (Bofill Powell+MS for transition states).

8 9

D2Corr (No update, use initial Hessian). D2Corr (New if energy rises, otherwise BFGS).

L121: Multi-time step parameter (NDtrC,NDtrP) 0

No multi-time stepping

NN

Iterate density constraints NN times per step

MM00 Do gradient once every MM steps IOp(1/14)

L103: Max. number of bad steps to allow before attempting a linear minimization (i.e., no quadratic step). 0

Default (0 for TS, 1 for minima).


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N

Allow N -- linear only starts with the N+1st.

IOp(1/15)

L103,L109: ABORT IF DERIVATIVES TOO LARGE -1 or 0

No force test at all.

N

FMAXT = 0.1 * N

IOp(1/16)

L103,L113,L114: MAXIMUM ALLOWABLE MAGNITUDE OF THE EIGENVALUESOF THE SECOND DERIVATIVE MATRIX. IF THE LIMIT IS EXCEEDED, THE SIZE OF THE EIGENVALUE IS REDUCED TO THE MAXIMUM, AND PROCESSING CONTINUES. 0 N

EIGMAX = 25.0 HARTREE / BOHR**2 OR RADIAN**2 EIGMAX = 0.1 * N

IOp(1/17)

L103,L113,L114: MINIMUM ALLOWABLE MAGNITUDE OF THE EIGENVALUES OF THE SECOND DERIVATIVE MATRIX. SIMMILAR TO IOp(16) 0

EIGMIN = 0.0001

N

EIGMIN = 1. / N

IOp(1/18)

L103: Coordinate system. 0

Proceed normally

1 Second derivatives will be computed as directed on the variable definition cards. No optimization will occur. 10

Do optimization in cartesian coordinates.

20

Do full optimization in redundant internal coord.

30

Do full optimization in pruned distance matrix coords.

40

Do optimization in Z-matrix coordinates.


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50

Do full optimization in redundant internal coords with large molecular tools.

100

Read the AddRedundant input section for each structure.

1000 Do not define H-bonds 2000 Define H-bonds with no related coordinates (default) 3000

Define H-bonds and related coordinates

10000 Reduce the number of redundant internals 20000 Define all redundant internals 100000

Old definition of redundant internals.

0000000 Default (2000000). 1000000 Skip MM atoms in internal coordinate definitions and do microiterations the old way, in L103. 2000000

Include MM atoms in internal coordinate definitions (no microiterations).

3000000 Skip MM atoms in internal coordinate definitions and do microiterations the new way, in L120. 4000000

Microiterations for pure MM, done in L402.

IOp(1/19)

L103: SEARCH SELECTION 0

Default (same as 6).

2

LINEAR AND STEEPEST DESCENT.

3

STEEPEST DESCENT AND LINEAR ONLY WHEN ESSENTIAL.

4

Quadratic if curvature is correct; RFO if not. Linear as usual.

5

Quadratic if curvature is correct; RFO if not. No linear search.

6

RFO and linear.

7

RFO without linear.


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8

Newton-Raphson and linear.

9

Newton-Raphson only.

10

GDIIS and linear

11

GDIIS only.

13

First-order simultaneous optimization.

L113,L114: Search Selection: 0

P-RFO OR RFO STEP ONLY

(DEFAULT)

1 P-RFO OR RFO STEP FOR "WRONG" HESSIAN OTHERWISE NEWTONRAPHSON IOp(1/20)

L101, L106, L108, L109, L110: INPUT UNITS 0

ANGSTROMS DEGREES

1

BOHRS

2

ANGSTROMS RADIANS

3

BOHRS

DEGREES

RADIANS

IOp(1/21)

L103,L113,L114: EXPERT SWITCH. 0

NORMAL MODE.

1 EXPERT MODE: CERTAIN CUTOFFS USED TO CONTROL THE OPTIMIZATION WILL BE RELAXED. THESE INCLUDE FMAXT, DXMAXT, EIGMAX AND EIGMIN. IOp(1/22)

L107: Whether to reorder coordinates for maximum coincidence. 0

Yes.

1

Assume reactant order equals product order.


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2

Read in a re-ordering vector from the input.

L115: KIND OF SEARCH: 0

BOTH DIRECTIONS AND GENERATE SEARCH VECTOR

1

FORWARD DIRECTION AND GENERATE S. VECTOR

2

BACKWARD DIRECTION AND GENERATE S. VECTOR

3

BOTH DIRECTIONS AND GENERATE S. VECTOR

4

FORWARD DIRECTION AND READ S. VECTOR 8F10.6

5

FORWARD DIRECTION AND READ S. VECTOR 8F10.6

6 7

BACKWARD DIRECTION AND READ S. VECTOR 8F10.6 BOTH DIRECTIONS AND READ S. VECTOR 8F10.6

IOp(1/23)

L112: Derivative availability. 0

Energy only.

1

Energy + Forces.

2

Energy + Forces + Force constants

IOp(1/24)

Whether to round tetrahedral angles. 0

Default (Yes).

1

Yes, round angles within 0.001 degree.

2

No.

IOp(1/25)

Wether SCRF is used with numerical polarizability: 0

No.


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1

Yes, the field in /Gen/ must be cleared each time.

IOp(1/26)

Accuracy of function being optimized: -NNMM Energy 10**-(NN), Gradient 10**(MM). -1 Read in values 0


1

Normal accuracy for HF (energy and gradient both 1.d-7).

2

Standard grid accuracy for DFT (Energy 1.d-5, gradient 1.d-4)

3

Fine grid accuracy for DFT (Energy 1.d-7, gradient 1.d-6)

IOp(1/27)

= IJKL (i.e. 1000*I+100*J+10*K+L) Transition state searching using QST and redundant internal coordinates L= 0,1 Input one structure, either initial guess of the minimizing structure or transition structure without QST. L= 2 Input 2 structures, the first one is the reactant, the second one is the product. The union of the two redundant coordinates are taken as the redundant coords for the TS. The values of the TS coord are estimated by interpolating the sturcture of R and P. R and P are used to guide the QST optimization of the TS. L= 3 Input 3 structures. The first one is reactant the second one is the product. The third one is the initial guess of the transition structure. R and P are used to guide the QST optimization of the TS. K = 1-9 Interpolation of initial guess of TS between R and P (TS=0.1*J*R + 0.1*(10J)*P, default J=5) J=1

LST constraint in internals

J=2

QST constraint in internals

J=3

LST constraint in distance matrix space

J=4

QST constraint in distance matrix space


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I = 0-9 Control parameters for climbing phase of QST (e.g. QSTRad = 0.01*I, default QSTrad = 0.05) IOp(1/28)

L103: Number of translations and rotations to remove during redundant coordinate transformations: -2

0.

-1

Normal (6 or 5 for linear molecules).

0

Default, same as -1.

N

N.

IOp(1/29)

L101: SPECIFICATION OF NUCLEAR CENTERS 0

BY Z-MATRIX

1

BY DIRECT COORDINATE INPUT (must set IOp(29) in L202).

2

GET Z-MATRIX AND VARIABLES FROM THE CHECKPOINT FILE.

3

GET CARTESIAN COORDINATES ONLY FROM THE CHECKPOINT FILE.

4

By model builder, model A.

5

By model builder, model B.

6 Get Z-matrix from the checkpoint file, but read new values for some variables from the input stream. 7

Get all input (title, charge and multiplicity, structure) from the checkpoint file.

10

Print details of the model building process.

000 Default (same as 100). 100 Do not abort job if model builder generates a z-matrix with too many variables. 200 Abort job if model builder generates a z-matrix with too many variables. 1000

Read optimization flags in format 50L1 after the z-matrix.


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2000

Set all optimization flags to optimize.

3000

Purge flags except the frozen variables.

4000

Rebuild the coordinate system.

5000

(2+3) Purge all flags but keep the coordinate definition.

00000

Default, same as 10000.

10000

Mark Z-matrix constants as frozen variables rather than wired-in constants.

20000

Do not retain symbolic constants.

100000 Generate a symbolic z-matrix using all Cartesians if none is present on the checkpoint file (a hack to make IRCs work with Cartesian input). 200000

Same as one, but retain the redudant internal coordinate definitions.

IOp(1/30)

L103: ARE THE READ-WRITE FILES TO BE UPDATED? THIS OPTION IS SET FOR THE LAST CALL TO 103 IN FREQUENCY CALCULATIONS IN ORDER TO PRESERVE THE VALUES OF THE VARIABLES FOR ARCHIVING. It also suppresses error termination on large gradients. 0

YES

1

NO

IOp(1/32)

TITLE CARD PUNCH CONTROL. 0

DON'T PUNCH.

1

PUNCH.

IOp(1/33)

L101: L102 L103 L106 L109 L110 L113 L114 0

OFF

1

ON


DEBUG PRINT

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IOp(1/34)

L101 L102 L103: DEBUG + DUMP PRINT 0

OFF

1

ON

IOp(1/35)

RESTART (L102-L112). 0

NORMAL OPTIMIZATION.

1 FIRST POINT OF A RESTART. GET GEOMETRY, WAVEFUNCTION, ET. FROM THE CHECKPOINT FILE. IOp(1/36)

CHECKPOINT. 0

NORMAL CHECKPOINT OF OPTIMIZATION.

1

SUPPRESS CHECKPOINTING.

IOp(1/37)

D2E CLEANUP (obsolete) 0

NO CLEANUP.

1 THIS IS THE LAST POINT AT WHICH ANALYTIC SECOND DERIVATIVES WILL BE DONE. DELETE THE D2E FILE AND THE BUCKETS AND TRUNCATE THE READ/WRITE FILES. IOp(1/38)

Entry control option (currently only by L106, L107, L108, L109, L110, L111, and L112 but not L102, L103, and L105). 0

Continuation of run.

1

Initial entry.

N>1 . In L103: Initial entry of guided optimization using N levels.


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N0 In L106: differentiate Nth derivatives once. In L110 and L111: differentiate energy N times. 000

In L106: differentiate wrt nuclear coordinates.

100 200

In L106: differentiate wrt electric field. In L106: differentiate wrt field and nuclear.

IOp(1/39)

Step size control for numerical differentiation. (L106, L109, L110, L111). Path step size in L115. 0 Use internal default (0.001 Angstroms in L106, 0.005 A in L109, 0.01 Angstrom in L110, 0.001 au in L111). N Use step-size of 0.0001*N (angstroms in L106, L109, L110, electric field au in L111). -1

Read stepsize (up to 2 for L106, 1 for others), free-format.

-N>1 Use step-size of 0.0001*N atomic units everywhere. IOp(1/40)

L113, L114: Hessian recalculation. -1

Pick up analytic second derivatives every time.

0

Just update. The default, execpt for CalcAll.

N

Recalculation the Hessian every N steps.

L116: Whether to read initial E-field: 0

Start with 0.0.

1

Read from checkpoint file.

2

Read from input stream.

IOp(1/41)

Step number of optimization from which to take geometry. -1 for the initial geometry


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IOp(1/42)

L103, L115: Number of points along the reaction path in each direction. Default is 6. L117: Cutoff to be used in evaluating densities. 0

1.0D-10 N 1.0D-N

IOp(1/43)

L116: Extent of Reaction Field. 0

Dipole

1

Quadrupole

2

Octapole

3

Hexadecapole

L117: How to define Radii 0

Default is 11

1

Use internally stored Radii, centers will be on atoms

2

Read-in centers and radii on cards

10

Force Merz-Kollman radii (Default)

20

Force CHELP (Francl) recommended radii.

30

Force CHELPG (Breneman) recommended radii.

100 Read in replacement radii for selected atom types as pairs (IAn,Rad) or (Symbol,Rad), terminated by a blank line. 200 Read in replacment radii for selected atoms as pairs (I,Rad), terminated by a blank line. Initial radius of spheres to be placed around attractors to "capture" the gradient trajectories. The final radius is then automatically optimized separately for each atom. 0 NM

0.1 N.M = NM/10


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IOp(1/44)

IRC Type 0


1

Cartesian.

2

Internal.

3

Mass-weighted.

L117: Maximum distance between a nucleus and its portion of the isosurface - used in Trudge only to eliminate, from the outset, points which clearly lie in another basin. This parameter should be chosen with the parameter Cont in mind 0 10.0 au NM N.M au = NM/10 L121: Seed for random number generator (ISeed) -1

Use system time initialize iseed (Note each run will give different results)

0

Use default seed value (ISeed = 398465)

N

Set random number seed to N

IOp(1/45)

Read isotopes in L115. 0

Do not read isotopes.

1

Read Isotopes.

IOp(1/46)

Order of multipoles in numerical SCRF: 0

Dipole

1

Quadrupole

2

Octapole


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3

Hexadecapole.

IOp(1/47)

Number of redundant internal coordinates to allow for. 0

Default: 50000 N

N.

IOp(1/48)

IRCMax control. 1

Do IRCMax

20

Include zero-point energy.

CIOp(1/49)

Options to IRC path relaxation (IJKL) L

2/1 dont/do optimize reactant structure. Default: 1

K

2/1 dont/do optimize product structure. Default: 1

J

3/2/1 dont/QST3/QST2 optimize TS structure (for QST input). Default: 1

I

2/1 unimolecular/bimolecular reaction. Default: unimolecular

IOp(1/52)

L101 and L120: Type of ONIOM calculation: 0/1

One layer, normal calculation

2

Two layers

3

Three layers

00

Default (20)

10

Include electrostatics in model systems using MM charges.

20

No electrostatics included in the model systems


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100

Do full square for testing.

N000 Use atomic charge type N-1 during microiterations. The default is MK charges. IOp(1/53)

L120: Action of each invocation of L120: 0

Do nothing

1

Set up point MM on rwf from initial data

2 Set up point MM on rwf from initial data and restore point MM on chk file if ONIOM data is present there. 3

Restore point M from data on the rwf.

4

Integrate energy

5

Integrate energy and gradient

6

Integrate energy, gradient, and hessian

7

Restore point MM from RWF but do not create a new model system.

NN0 Save necessary information (some rwf's, energy, gradients, hessian) of point NN of the ONIOM grid. NN = MaxLev**2 + 1 (currently 17) to restore real system. MM000

Next point to do is MM.

Calc Level High

4--7--9*

||| Mid

2--5--8

||| Low SML

1--3--6 system size

IOp(1/54)


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Whether to recover initial energy during IRCMax from chk file: 0

No.

1

Yes.

IOp(1/55)

L103: Options for GDIIS: ICos*1000+IChkC*100+IMix*10+Method form. L115: IRC optimization. 0

Default, use gradients to find the next geometry.

1

Use displacements to find the next geometry.

IOp(1/56)

Set of atom type names to parse: 0

Accept any.

1

Dreiding/UFF.

2

Amber.

3

Amber allowing any symbol, for use with parameters in input stream.

IOp(1/57)

Whether to produce connectivity: 0

Default (4 if reading geom from chk file and connectivity is there, otherwise 3).

1

No.

2

Yes, read from input stream

3

Yes, generate connectivity.

4

Yes, read from checkpoint file.

5

Yes, read from rwf file.

10

Read modifications.


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100

Connectivity input is in terms of z-matrix entries, including dummy atoms.

IOp(1/58)

IRCMax control in L115. IOp(1/59)

Update of coordinates in L103 0

Default (1 for large opt, 2 for regular)

1

New versions.

2

Old version.

IOp(1/60)

Interpret extra integer and fp values in z-matrix as scan information. 0

Default (No).

1

Yes.

2

No.

IOp(1/61)

How ONIOM should leave the rwf at the end of each geomtry: 0

Default (1).

1

Normal: leave the rwf set up for the low-level calculation on the real system.

2 MOMM: leave the rwf set up for the real system, but with NBasis and NBsUse for the high-level calc on the model system. Useful for treating the full system as having electrons only on the QM atoms. IOp(1/62)

Counterpoise control. NN

NN fragments, NN < 50.

IOp(1/63)


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Step in counterpoise calculation: MNN

M = order of derivatives (1=Energy, 2=Gradient,

NN = 0

Supermolecule

1-NFrag

Fragments with ghost atoms

NFrag+1 - 2*NFrag -- lone fragments IOp(1/64)

Molecular mechanics force field selection: 0

None.

1 2

Dreiding. UFF.

3

AMBER.

4

MM2 (NYI).

5

MM3 (NYI).

6

MMFF (NYI).

7

Quartic fitting field (NYI).

000

Use only hard-wired.

100

Use soft and hard-wired, hard-wired has priority.

200

Use soft and hard-wired, soft has priority.

300

Use only soft. Lowest 2 digits then have no meaning.

0000 Do not read modifications to parameter set. 1000 Read modifications to parameter set. 00000 With soft parameters, abort when different parameters match to the same degree. 10000 Use the first when there are equivalent matches.


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20000 Use the last when there are equivalent matches. If IOp(67)=3, then the default is to apply soft parameters with higher priority. IOp(1/65)

Control of which terms are included in MM, corresponding to the 'classes' in FncInf. 0

Do all (default)

1

Non-bonded

10

Stretching

100

Bending

1000 Torsion 10000 Out-of-plane IOp(1/66)

Whether to generate QEQ charges, over-written the values in AtChMM, or to use the values already there. 0

Default (2, 1==> 221)

1

Do QEq.

2

Don't do QEq.

00

Default (10)

10

Do for atoms which were not explicitly typed.

20

Do for all atoms regardless of typing.

000

Default (100)

100

Do for atoms which have charge specified or defaulted to 0.

200

Do for all atoms regardless of initial charge.

IOp(1/67)

Source of MM parameters.


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0

Default: 2 if reading geom from chk file, else 1.

1

Generate here, reading from input if requested by IOp(64).

2

Copy from chk file.

3

Pick up non-standard parameters from chk file.

IOp(1/70)

L118 Type of sampling (Nact) 0

Defalt (same as 3)

1

Orthant sampling

2 3

Microcanonical normal mode sampling Fixed normal mode energy

4

Local mode sampling ( now only Nact = 0 or 3 OK )

IOp(1/71)

Whether to print out input files for each structure along an IRC: 0

No.

1

Yes.

IOp(1/72)

L103: Algorithm choice for microiterations. L121: Lagrangian constrain method for ADMP (ICType) Half*Gamma*Tr[(P*P-P)**2] + Lambda*[Tr(P)-Ne] + Eta*Tr(P*P-P) 0 Default Same as 7 if no Mass-Weighting (IOp(76) < 0) Same as 10 if MassWeighting (IOp(76) > 0) 1

Use Lambda and Eta only. (Gamma=0)

2

Use Lambda, Eta, Gamma. Gamma = .2

3

Use Lambda, Eta, Gamma. Gamma = 1. Constraints for scalar Mass case:


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4

Use exact constraint Sum(ij)[Vij*(P**2-P)ij]

5-7 Iterative Scheme same as 4. Different initial guesses. 7 is default for scalar mass case. Constraints for tensorial Mass: 8-11 default.Mass-weighting constraints. Documentation maybe found in DVelV1. 10 is IOp(1/73)

L103: NInit for microiterations. L121: Initial Kinetic energy of the Nuclei (EStrtC) 0

Default (.1 Hartree)

N>0 N*micro-Hartree N<0 0.0 Hartree IOp(1/74)

Charge scaling for charge embedding in ONIOM. IJKLMN 6th through 1st nearest neighbors of current layer scaled by I*0.2, J*0.2, etc. 0 ==> 5 (no scaling); all layers are scaled by at least as much as ones farther out. The default is 500. M

Factor for charges one bond away from link atom

L0

Factor for charges two bonds away from link atom

K00 Factor for charges three bonds away from link atom IJ etc. The actual factors used are: 0: 1.0 1: 0.0 2: 0.2 3: 0.4 4: 0.6 5: 0.8 6-9: 1.0 IOp(1/75)

ADMP control flag (ICntrl) 0

Standard ADMP

1

Read converged density at every step

2

Fix the nuclear coordinates

3

Test time reversability (MaxStp must be even)


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00

Default (20).

10

Read stopping parameters from input.

20

Do not read stopping parameters.

IOp(1/76)

+/- XXXXZYYYY = Ficticous electron mass (EMass) YYYY Default (1000) IOp(76)>0 YYYY*.0001 AMU MW core functions more than valence functions. IOp(76)<0 YYYY*.0001 AMU. Use uniform scaling for all basis functions (Note YYYY > 9999 makes no sense) Z

Mass-weighting option. If IOp(76)<0, Z is meaningless.

XXXX If PBC: Mass of Box Coordinates (BoxMas) = XXXX*.0001 AMU BoxMas=0 Box coordinates not propagated (default). IOp(1/77)

Initial Kinetic energy of the density matrix (EStrtP) (For UHF, Alpha and Beta each get half this energy) and Option Number to compute initial kinetic energy. Format of Input: XXYYYY (six digits) IWType = XX N = YYYY (For UHF, Alpha and Beta each get half this energy) 0

Default (0.0 Hartree)

N>0 N*micro-Hartree IWType is used to figure out how the initial velocity is is computed (in gnvelp). If XXYYYY < 0 : Initial velocity = 0.0 Hartee (i.e., currently same as N=0 above) IOp(1/78)

Sparse in L121 -N

Sparse here with cutoff 10**(-N), full elsewhere


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0

Use full matrices or spase based on standard settings.

1

Use sparse fixed form

IOp(1/79)

IRCMax convergence in L115 Stopping criteria in L118 and L121. IOp(1/80)

L106: 0/1/2 Cartesian/Normal mode/Internal coordinate differentiation. 2 is NYI. L118: .eq.1 to surpress the 5th order correction after surface hop has been made in Trajectory Surface Hopping calculations. Needs also IOp(10/80=1) Nuclear Kinetic Energy Thermostat Option. (Currently only Velocity scaling is implemented) 0

No Thermostat.

11XXXXX Velocity scaling, but only for the first XXXXX simulation steps. (This options is useful, if thermostating in only required during equilibration. 1000000

Velocity scaling, all the way through the simulation.

IOp(1/81)

Nuclear KE thermostat in ADMP -- temperate is checked and scaled every IOp(81) steps. IOp(1/82)

Temperature for nuclear KE thermostat in L121. IOp(1/83)

Whether to read in frequencies for electric and magnetic perturbations. 0

Default (No).

1

Yes.

2

No.

IOp(1/84)

Differentiation of frequency-dependent properties.


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0

No.

N

Mask for which properties on file 721 will be differentiated.

IOp(1/85)

Band gap calculation in PBC ADMP: 0

Default (No).

1

Diagonalizae Fock matrix to get band gap, evolution, etc.

2

No.

IOp(1/86)

Printing for NMR for ONIOM. 0

Default (1).

1

Print tensors and eigenvalues.

2

Print eigenvectors as well.

IOp(1/87)

ONIOM integration of density. 0

Do not integrate.

1

Integrate current densities.

2

Integrate densities specified by following digits:

K0

Density to use from gridpoint 1

L00 Density to use from gridpoint 2 M000 etc. K,L,M,etc: 0: SCF 1: MP first order


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2: MP2 3: MP3 4: MP4 5: CI one-particle 6: CI 7: QCI/CC 8: Correct to second order IOp(1/88)

Whether to read in atomic masses (isotopes): 0 Default (1 if geometry read from input, 4 if geometry read from chk) 1

Use most abundant isotopes.

2 Read isotopes from input. The temperature and pressure are read first, for backwards compatibility. 3

Read isotopes from rwf.

4

Read isotopes from chk.

IOp(1/89)

Maximum allowed deviation from average nuclear KE during ADMP, in Kelvin. IOp(1/90)

To read in the velocity in cartesian coordinates Nuclear Kinetic Energy Thermostat Option. Average energy (in microhartree) to be maintained during Simulation, as required by IOp(80). IOp(1/91)

Thermostat Option. IOp(1/92)


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Maximum allowed deviation from average nuclear KE specified in IOp(81). Also in microhartree. IOp(1/94, 95, 96, 97, 98) IOp(94): IOp(95): IOp(96):

Davidson control for quadratic micro-iterations (see MMOpt2) RFO/Davidson control for quadratic micro-iterations (see MMOpt2) Davidson control for coupled QM/MM macro step (see MMOpt2)

IOp(97):

RFO/Davidson control for coupled QM/MM macro step (see MMOpt2) IOp(98):

Control of quadratic micro-iterations and coupled QM/MM quadratic macro step. <0

Do not use dynamic convergence criteria for the micro-iterations.

0

Default(15).

1

Regular non-coupled macro step.

2

Coupled macro step, full diagonalization.

3

Coupled macro step, direct /w full Hessian incore.

4

Coupled macro step, direct /w MM Hessian incore.

5

Coupled macro step, fully direct.

10

Regular micro-iterations.

20

Quadratic micro-iterations, full diagonalization.

30

Quadratic micro-iterations, direct /w prepared Hessian incore.

40

Quadratic micro-iterations, direct /w raw MM Hessian incore.

50

Quadratic micro-iterations, fully direct.

IOp(1/101, 102, 103, 104)

Phase control in L115 and L118: N1, N2, N3, N4 IOp(1/105)


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Reaction direction 00

Default (Same as 10)

10

Forward direction

20 Reverse direction Damped-Velocity Verlet (DVV) options for Dynamic Reaction Path Following 0

Default (Same as 2)

1

Use DVV

2

Do not use DVV

00


10

Follow the rxn path in the forward direction

20

Follow the rxn path in the reverse direction

000


100

Time step correction not used

200

Time step correction used but not to recalculate current DVV step

300 Time step correction used and current DVV step recalculated 0000 Default (Same as 1000) 1000 Use DVV stopping criteria 2000 Do NOT use DVV stopping criteria IOp(1/106)

Damping constant for DVV Dynamic Rxn Path following (v0) 0

Default v0=0.04 (N=400)

N

v0 is set to N*0.0001

IOp(1/107)

Error tolerance for DVV time step correction (Error)


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0

Default Error=0.003 (N=30) N

Error=N*0.0001

IOp(1/108)

Gradient magnitude for DVV stopping criteria (Crit1) 0

Default (N=15) N

N*0.0001

IOp(1/109)

Force-Velocity angle for DVV stopping criteria (Crit2) 0 N

Default (90 Degrees) Use N Degrees

IOp(1/110)

Scaling of rigid fragment steps during microiterations. 0

Do not scale

1

Scale with 1/NRA

2

Scale with 1/Sqrt(NRA)

-n

Scale with 1/n

(NRA = number of atoms in fragment)

IOp(1/111)

Step-size to use with steepest descent when L103 is having trouble: -N

Scale up to RMS step of N/1000 if DXRMS is less.

-1

Effectively disables the scaling

0

Default (50)

N

Scale up or down to maximum change in a variable of N/1000

IOp(1/112)


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Temperature for thermochemistry. 0

Default (standard temperature, unless read in).

N

N/1000 degrees.

IOp(1/113)

Pressure for thermochemistry. 0

Default (1 atomosphere, unless read in).

N

N/1000 atmospheres.

IOp(1/114)

Scale factor for harmonic frequencies for use in thermochemistry and harmonic vibration-rotation analysis. 0

Default (1 unless specified by IOp in overlay 7 or read in). N

N/1000000.

Overlay 2 9 10 11 12 13 14 15 16 17 18 19 20 29 30 40 41 IOp(2/9)

Printing of distance and angle matrices. 0

Default: same as 2.

1

Do not print the distance matrix.

2

Print distance matrix.

00

Default: same as 20.

10

Do not print the angle matrix.

20

Print the angle matrix, using z-matrix connectivity if possible.

30

Use cutoffs instead of the z-matrix for determining which angles to print.


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000

Default: same as 100.

100

Do not print dihedral angles.

200

Print dihedral angles, using the z-matrix for connectivity info.

300

Print dihedral angles, using a distance cutoff for connectivity info.

0000 Default: print only for small cases 1000 Do not print the cartesian coordinates in the input orientation 2000 Do print the cartesian coordinates in the input orientation IOp(2/10)

TETRAHEDRAL ANGLE FIXING 0 Default (don't test). 1

ANGLES WITHIN 0.001 DEGREE OF 109.471 WILL BE SET TO ACOS(-1/3).

2

DO NOT TEST FOR SUCH ANGLES.

IOp(2/11)

PRINTING OF Z-MATRIX AND RESULTANT COORDINATES. 0

Default (print if 50 atoms or less)

1

Print

2

Don't print

IOp(2/12)

CROWDING ABORT CONTROL 0


1

Abort the run for zero atomic distances only

2

Abort the run if any atoms are within 0.5 A.

3

Do not abort the run regardless of 0 distances.


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IOp(2/13)

PUNCH COORDINATES. 0

NO

1 YES, IN 'ATOMS' FORMAT (3E20.12). NOTE, ATOMS WILL NOT TAKE THE ATOMIC NUMBERS, SO THEY ARE NOT PUNCHED. 2 YES, IN FORMAT SUITABLE FOR COORD INPUT TO Gaussian. THE ATOMIC NUMBERS AND COORDINATES ARE PUNCHED IN FORMAT (I2,3E20.12) IOp(2/14)

Internal coordinate linear independance. 0


1

Perform the test, but do not abort the job.

2

Do not perform the test.

3 If internal coordinates are in use, test the variables for linear independance and abort the job if they are dependant. 10 Compute nuclear forces as well as second derivatives for the test. This is not correct for the linear independance check, but is useful for debugging the derivative transformation routines. 100 Abort the job if the number of z-matrix variables is not exactly the number of degrees of freedom (i.e., this is not a full optimization). IOp(2/15)

SYMMETRY CONTROL. -1 Turns on symmetry; same as 0 for molecules but turns on assignment of space group ops. for PBC. 0

Leave symmetry in whatever state it is presently in.


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1 Unconditionally turn symmetry off. Note that symm is still called, and will determine the framework group. However, the molecule is not oriented. 2

Bring the molecule to a symmetry orientation, but then disable further use of

symmetry. 3 Don't even call symm. 4 Call Symm once with loose cutoffs, symmetrize the resulting coordinates, then confirm symmetry with tight cutoffs. 5 Recover the previous symmetry operations from the rwf, and confirm that the new structure has the same symmetry. 6

Same as 5, but get symmetry info from the chk.

00

Default (10)

10

Do re-orientation for PBC.

20

Suppress re-orientation for PBC.

100 Turn on symmetry operations for PBC. IOp(2/16)

action taken if the point group changes during an optimization. 0 Abort the job. 1

Keep going.

2

Keep going and leave symmetry on, using the old symmetry.

3

Keep going and leave symmetry on, using the new symmetry.

IOp(2/17)

Tolerance for distance comparisons in symmetry determination. 0

Default (determined in the symmetry package, currently 1.d-8). N>0

N<0

10**-N. 10**N, use same tolerance for orientation.


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IOp(2/18)

Tolerance for non-distance comparisons in symmetry determination. 0

Default (determined in the symmetry package, currently 1.d-7). N>0

N<0

10**-N. 10**N, use same tolerance for orientation.

IOp(2/19)

Largest allowed point group, as Hollerith string. IOp(2/20) Number (1-3 for X-Z) of axis to help specify which subgroup of the type specified in IOp(19) to use. IOp(2/29)

Update of coordinates from current Z-matrix. 0

Default (1)

1

No.

2

Yes, but remove z-matrix.

3

Yes.

IOp(2/30)

Read in vector of atom types (for debugging). 0

No

1

Yes, format (50I2)

IOp(2/40)

Save (initial) structure and possible constraints in rwf 698: 0

Default (No).

1

Yes.


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2

Pick up structure from rwf698 on the chk file.

3

Read in structure from input stream.

IOp(2/41)

Force constants for Harmonic constraints. -2

Read in force constants for each cartesian coordinates

-1

No constraints.

0

Default (no constraint unless reading constraint from chk file).

N

N/1000 Hartree/Bohr**2

Overlay 3 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 67 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 IOp(3/5)

TYPE OF BASIS SET. The same numbers are used for all basis sets, whether intended for use in expanding AOs (IOp(5)) or in expanding the density (IOp(82)). 0 1 2 3 4

MINIMAL STO-2G TO STO-6G EXTENDED 4-31G,5-31G,6-31G MINIMAL STO-NG (VALENCE FUNCTIONS ONLY) EXTENDED LP-N1G (VALENCE BASIS FOR CORELESS HARTREE-FOCK PSEUDOPOTENTIALS) EXTENDED 6-311G (UMP2 FROZEN CORE OPTIMIZED) BASIS for first row, MacLean-Chandler (12s,9p)-->(631111,52111) for second

row. USE IOp(8) TO SELECT 5D/6D. 5

SPLIT VALENCE N-21G (OR NN-21G) BASIS FOR FIRST OR SECOND ROW

ATOMS. (VARIOUS IMPLEMENTATIONS MAY OMIT SECOND ROW ATOMS.) SEE IOp(6) FOR DETERMINATION OF THE NUMBER OF GAUSSIANS IN THE INNER SHELL. 6 LANL ECP basis sets. IOp(6) selects options. 7 GENERAL--SEE ROUTINE GenBas FOR INPUT INSTRUCTIONS.


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8 Dunning/Caltech basis sets. Type selected by IOp(6). 9 Stevens/Basch/Krauss/Jasien/Cundari ECP basis sets for H-Lu. Type selected by IOp(6) for H-Ar. Literature citations in CEPPot. 10 CBS basis #1 -- 6-31+g(d,p) on H, He 6-311+G(2df) on Li - Ne 6-311+g(3d2f) on Na 11 - Ar CBS basis #2 -- 6-31G, use daggers if any polarization 12 CBS basis #3 -- 6-311++G(2df,2p) on H - Ne 6-311++g(3d2f) on Na - Ar 13 CBS basis #4 -- 6-31+G(d,p) on H - Si 6-31+G(df,p) on P, S, Cl 14 CBS basis #5 -- Large APNO basis set 15 CBS basis #6 -- Core correlation basis set 16 Dunning cc basis sets, type selected by IOp(6) (=0-4 for V{D,T,Q,5,6}Z) and augmented if IOp(7)=10. IOp(3/6)=5 for MTsmall basis set. 17 Stuttgart/Dresden ECP basis sets. IOp(6) specifies type. Literature citations in SDDPot. 18 Ahlrichs SV basis sets. 19 Ahlrichs TZV basis sets. 20 MIDI! basis sets. 21 EPR-II basis sets. 22 EPR-III basis sets. 23 UGBS basis set. 24 G3large basis set. 25 G3MP2large basis set. 26 Coreless: Li,Be 2SDF, B-Ne 2MWB, rest LANL1MB. 27 DGauss basis sets, selected by IOp(6) 28

Auto-generated, useful only for density basis sets.

IOp(3/6)

NUMBER OF GAUSSIAN FUNCTIONS N STO-NG,N-31G,LP-N1G,STO-NG-VALENCE, N-21G. NOTE IF IOp(5)=3 AND IOp(6)=8 ; LP-31G FOR LI,BE,B,NA,MG,AL LP-41G FOR OTHER ROW1 AND TWO ATOMS. DEFAULT IOp(6)=0 IF IOp(5)=0:OPTIONS N=3 STO-3G IF IOp(5)=1: N=4 4-31G IF IOp(5)=2: N=3 STO-3G (VALENCE) IF IOp(5)=3: N=3 IF IOp(5)=5: N=3


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WHEN IOp(5)=7 (GENERAL BASES), THIS OPTION IS USED TO CONTROL WHERE THE BASIS IS TAKEN FROM: 0 READ GENERAL BASIS FROM THE INPUT STREAM. 1 READ THE GENERAL BASIS FROM THE RW-FILES AND MERGE WITH THE COORDINATES IN BLANK COMMON TO PRODUCE THE CURRENT BASIS. 2 Read the general basis from the checkpoint file. 3 Same as 1, for density basis (generated here from 1) 4 Same as 2, for density basis (generated here from 2) 1x Read from the alternate file and remove functions/ECPs for inactive atoms. Used for counterpoise calculations, where one wants to modify the basis differently during different steps. This option is useful when doing general basis geometry optimizations or properties are

using a wavefunction on the checkpoint file. If non-standard ECPs are in use, they read along with the basis set information.

When IOp(5)=6 (LANL basis and potentials) this selects the type: 0

LANL1 ECP, MBS.

1

LANL1 ECP, DZ.

2

LANL2 ECP (where available, otherwise LANL1), MBS.

3 LANL2 ECP (where available, otherwise LANL1), DZ. When IOp(5)=8 (Dunning bases) this option selects the type: 0

Dunning full double-zeta.

1

Dunning valence double-zeta.

2

WAG basis (Dunning VDZ on first row, SHC ECP on second row). See Rappe, Smedley, and Goddard, J. Phys. Chem. 85, 1662 (1981) and J. Phys. Chem. 85,

3546 (1981). When IOp(5)=9 (CEP basis) this option selects the type (H-Ar only): 0

CEP-4G.

1

CEP-31G.


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2

CEP-121G.

When IOp(5)=17 (Stuttgart/Dresden ECP bases) this option selects the type according to: 6

SDD

7 SDD for Z > 18, D95 and no ECP otherwise. When IOp(5)=26 (Coreless basis) this selects the choice of basis (the same ECPs are used regardless): 0

Default (3)

1

Primitives which match the ECPs.

2

Functions from extended Huckel theory.

3 VSTO-4G basis for 1st row, along with LP-31G potential. When IOp(5)=7 (DGauss basis sets): 1

DGDZVP

2

DZVP2

3

DGTZVP

4

DGA1 (fitting basis)

5

DGA2 (fitting basis)

IOp(3/7)

DIFFUSE AND POLARIZATION FUNCTIONS. 0

NONE.

1

D-FUNCTIONS ON HEAVY ATOMS (2ND ROW ONLY FOR 3-21G).

2single 2DD-funcs. value). on heavy atoms (scaled up/down by a factor of 2 from the standard 3

ONE SET OF D-FUNCTIONS AND ONE SET OF F-FUNCTIONS ON HEAVY ATOMS (indicates an extra tight 2df with ccp basis sets.

4 TWO SETS OF D-FUNCTIONS AND ONE SET OF F-FUNCTIONS ON HEAVY ATOMS.


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5

Three sets of d functions.

6

Three sets of d functions and one set of f-functions.

7

Three sets of d functions and two sets of f-functions.

8

CBS-Q d(f),d,p polarization basis

9

Tight d for VnZ+1 (W1 theory)

10

A SET OF DIFFUSE SP FUNCTIONS ON HEAVY ATOMS.

20

Augment non-hydrogens only (cc basis sets only).

100

P-FUNCTIONS ON HYDROGENS.

200 2 SETS OF P-FUNCTIONS ON HYDROGENS. 300 ONE SET OF P-FUNCTIONS AND ONE SET OF D-FUNCTIONS ON HYDROGENS. 400 TWO SETS OF P-FUNCTIONS AND ONE SET OF D-FUNCTIONS ON HYDROGENS. 500

Three sets of p-functions.

600

Three sets of p-functions and one set of d-functions.

700

2d,d,p) -- 2d on 2nd and later atoms, 1d on 1st row atoms.

1000 A DIFFUSE S FUNCTION ON HYDROGENS. IOp(3/8)

SELECTION OF PURE/CARTESIAN FUNCTIONS. 0

1 2

SELECTION DETERMINED BY THE BASIS N-31G 6D/7F N-311G 5D/7F N-21G* 5D STO-NG* 5D LP-N1G* 5D LP-N1G** 5D GENERAL BASIS 5D/7F FORCE 5D. FORCE 6D.


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10 20

FORCE 7F. FORCE 10F.

IOp(3/9)

Where 308 should store dipole velocity integrals. 0 Usual place (572). -1

Write over the dipole length integrals (518).

N

Store in RWF N.

IOp(3/10)

Modification of internally stored bases (default 12000): 0

None.

1

Read in general basis data in addition to setting up a standard basis.

10

Massage the data in Common /B/ and Common /Mol/.

100

Add ghost atoms to /B/ so that every shell is on a separate center.

1000

Split S=P AO basis shells into separate S and P shells.

2000

Do not split S=P AO shells.

10000 Split S=P=D=

AO shells into S=P, D, F,

20000 Do not split AO S=P=D

shells.

100000 Uncontract the AO basis. 200000 Uncontract the density basis 300000 Uncontract both basis sets. DEFAULTS STO-NG STANDARD SCALE-FACTORS. For VSTO-nG, the values for H-Ar can be determined by Slater's rules: H=1.2, He=1.7, Li-Ne=0.325*(IA-1), Na-Ar=(0.65*I-4.95)/3


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ATOM

1S

2SP

H

1.24

HE

1.69

LI

2.69

0.80

BE

3.68

1.15

B

4.68

1.50

C

5.67

1.72

N

O F

6.67 7.66 8.65

3SP

1.95

2.25 2.55

NE

9.64

2.88

NA

10.61

3.48

1.75

MG

11.59

3.90

1.70

AL

12.56

4.36

1.70

SI

13.53

4.83

1.75

P

14.50

5.31

1.90

S

15.47

5.79

2.05

CL

16.43

6.26

2.10

A

17.40

6.74

2.33

INNER AREBEEN BEST SELECTED ATOM VALUES J.CHEM.PHYS. 38, 2686 (1963) OUTERSHELLS SHELL HAS ON THE BASIS OF NUMEROUS OPTIMIZATION STUDIES ON VARIED SMALL MOLECULES. N-31G (ALSO N-31G* AND N-31G**) STANDARD SCALE-FACTORS HYDROGEN 1S

1S*


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H

1.20

1.15

FIRST ROW ATOMS ATOM 1S

2SP

2SP*

B

1.00

1.03

1.12

C

1.00

1.00

1.04

N

1.00

0.99

0.98

O

1.00

0.99

0.98

F

1.00

1.00

1.00

SECOND ROW ATOMS ATOM 1S 2SP

3SP

3SP*

P

1.00

1.00

0.98

1.02

S

1.00

1.00

0.98

1.01

CL

1.00

1.00

1.00

1.01

LP-N1G SCALE=1.0 FOR LI-AR (INNER AND OUTER) STANDARD POLARIZATION EXPONENTS FOR N-31G* AND N-31G** BASES ATOM

VALUE

H

1.1

LI

0.2

BE

0.4

B 0.6 C-NE 0.8 STANDARD POLARIZATION EXPONENTS FOR STO-NG* BASIS. ATOM

VALUE


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NA, MG AL-CL

0.09 0.39

IOp(3/11)

CONTROL OF TWO-ELECTRON INTEGRAL STORAGE FORMAT. 0

REGULAR INTEGRAL FORMAT IS USED.

1 RAFFENETTI '1' INTEGRAL FORMAT IS USED. CAN ONLY BE USED WITH THE CLOSED SHELL SCF. 2 RAFFENETTI '2' INTEGRAL FORMAT. SUITABLE FOR USE WITH THE OPEN SHELL (UHF) SCF. 3SHELL RAFFENETTI '3' INTEGRAL FORMAT. SUITABLE USEaccepted WITH OPEN RHF SCF AND THE POST-SCF PROCEDURES, butFOR not yet by them. 9

USE ILSW TO DECIDE BETWEEN RAFFENETTI 1 AND 2.

IOp(3/12)

Flag for semi-empirical runs, to account for sparkles, translation vectors and d functions properly: 1

MNDO/AM1.

2

CNDO/2, INDO/2.

3

ZINDO/1, ZINDO/S.

IOp(3/13)

Nuclear center whose Fermi contact terms are to be added to the core hamiltonian. The magnitude is specified by IOp(3/15). IOp(3/14)

Addition of electrostatic integrals to core hamiltonian. 0 -1x

No. SCRF calculation -- multiply moments by fudge factor for charged species.


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-6 Read coefficients of field, starting with electric field, up through 34 elements (hexadecapoles) in free format, blank terminated. -5

Read components of electric field only from /Gen/ on checkpoint file.

-4 -3

Read components of moments off rwf 521 on chk file. Read components of electric field only from /Gen/.

-2

Read components of moments off rwf 521.

-1 Yes, read 12 cards with x,y,z components of electric field, followed by xx,yy,zz,xy,xz,yz electric field gradient, xxx,yyy,zzz,xyy, xxy,xxz,xzz, yzz,yyz,xyz field second derivatives, and xxxx,yyyy,zzzz,xxxy, xxxz, yyyx,yyyz,zzzx,zzzy,xxyy,xxzz,yyzz,xxyz,yyxz, zzxy field third derivatives in format (3D20.10). (These correspond to dipole, quadrupole, octopole, and hexadecapole perturbations). 1-34 Just component number n in the above order with magnitude given by IOp(3/15). The nuclear repulsion energy is also modified appropriately, and the electric field is stored in Gen(2-4). IOp(3/15)

Magnitude of electric field. N N * 0.0001. IOp(3/16)

Pseudopotential option 0

Default. ECPs if defined with the basis set.

1

Yes, read if general basis.

2

No.

IOp(3/17)

SPECIFICATION OF PSEUDOPOTENTIALS -1

Read potential in old format.


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0

Default, based on IOp(3/5).

1

USE INTERNALLY STORED 'CORELESS HARTREE-FOCK'

2

Goddard/Smedley SECE/SHC potentials.

3

Stevens/Basch/Krauss CEP potentials.

4

LANL1 potentials.

5

LANL2 potentials.

6-7

unused

8

READ IN FROM CARDS (SEE PINPUT FOR DETAILS)

9 10

Dresden/Stuttgart potentials - SDD combination Dresden/Stuttgart potentials - SDD for Z > 18, D95V, no ECP otherwise.

11

Dresden/Stuttgart potentials - SDF

12

Dresden/Stuttgart potentials - SHF

13

Dresden/Stuttgart potentials - MDF

14

Dresden/Stuttgart potentials - MHF (first set)

15

Dresden/Stuttgart potentials - MHF (second set)

16

Dresden/Stuttgart potentials - MWB (first set)

17

Dresden/Stuttgart potentials - MWB (second set)

18

Dresden/Stuttgart potentials - MWB (third set)

19

Pseudopotentials for all coreless basis.

20

Alternative potentials for coreless basis.

IOp(3/18)

PRINTING OF PSEUDOPOTENTIALS 0

PRINT ONLY WHEN INPUT IS FROM CARDS or if GFPrint was specified.


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1

PRINT

2

DON'T PRINT

IOp(3/19)

SPECIFICATION OF SUBSTITUTION POTENTIAL TYPE 0

DONT USE ANY SUBSTITUTION POTENTIALS

N REPLACE THE STANDARD POTENTIAL OF THIS RUN (EG.CHF), WITH A SUBSTITUTION POTENTIAL OF TYPE N WHEREVER SUCH A SUBSTITUTION POTENTIAL EXISTS. IOp(3/20)

Size of buffers for integral file. 0 Default (Machine dependant; 16384 integer words on VAX, 55296 words on Cray). N

N integer words.

IOp(3/21)

Size of buffers for integral derivative file. No longer used. 0 N

Default (3200 integer words). N integer words.

IOp(3/22)

CONTROL OF THE PRE-CUTOFF IN THE TWO-ELECTRON D-INTEGRAL PROGRAM. Used only in L312. 0

NO PRE-CUTOFF.

1

PRE-CUTOFFS DESIGNED FOR THE 6-31G* BASIS.

IOp(3/23)

Disable use of certain basis functions.


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0

Use all basis functions.

1 Read in a list of basis function numbers in Format (10I5), terminated by a blank line, and set their dialgonal core Hamiltonian elements to +100.0. IOp(3/24)

Printing of gaussian function table. 0

Default (don't print).

1

Print old-fashioned table.

10

Print as GenBas input.

100 Print in more readable format. 1000 Print shell coordinates. IOp(3/25)

NUMBER OF LAST TWO-ELECTRON INTEGRAL LINK. -2

Use integrals from a previous job read /IBF/ from the checkpoint file.

-1 We are re-using integrals produced earlier in the current calculation; use the /IBF/ already on the RWF. 0

WE ARE NOT USING TWO-ELECTRON INTEGRALS.

1

Direct SCF.

>0

LINK NUMBER.

IOp(3/26)

ACCURACY OPTION. 0

DEFAULT. INTEGRALS ARE COMPUTED TO 10**-10 ACCURACY.

1

TEST. DO ALL INTEGRALS AS WELL AS POSSIBLE in L311.

2

STO-3G. USE OLD very inaccurate CUTOFFS IN LINK 311.

10

TEST. DO ALL INTEGRALS AS WELL AS POSSIBLE in L314.


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20

Sleazy. Use looser cutoffs in L314.

IOp(3/27)

HANDLING OF SMALL TWO-ELECTRON INTEGRALS. 0

DISCARD INTEGRALS WITH MAGNITUDE LESS THAN 10**-10.

N

DISCARD INTEGRALS WITH MAGNITUDE LESS THAN 10**-N.

IOp(3/28)

Special SP code control. 0

Default, use IsAlg.

1

All integrals with d's -- L311 does nothing.

2

SP integrals in link 311, d and higher elsewhere.

IOp(3/29)

Accuracy in L302: 0

Default (10**-12). N

10**-N.

IOp(3/30)

CONTROL OF TWO-ELECTRON INTEGRAL SYMMETRY. 0

TWO-ELECTRON INTEGRAL SYMMETRY IS TURNED OFF.

1 TWO-ELECTRON INTEGRAL SYMMETRY IS TURNED ON. NOTE, HOWEVER, THE SET2E WILL INTERROGATE ILSW TO SEE IF THE SYMMETRY RW-FILES EXIST. IF THEY DON'T, SYMMETRY HAS BEEN TURNED OFF ELSEWHERE, AND SET2E WILL ALSO TURN IT OFF HERE. IOp(3/31)

USE OF SYMMETRY IN COMPUTING GRADIENT (Obsolete). IOp(3/32)


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Whether to check the eigenvalues of the overlap matrix: 0

Default (4).

1

Yes.

2

No.

3

Yes, and reduce expansion space if linear dependence is found (NYI).

4

Yes, and use Schmidt orthogonalization to reduce expansion space.

5

Yes, using SVD to reduce expansion space.

IOp(3/33)

INTEGRAL PACKAGE PRINTING. 0 NO INTEGRALS ARE PRINTED. 1

PRINT ONE-ELECTRON INTEGRALS.

3

PRINT TWO-ELECTRON INTEGRALS IN STANDARD FORMAT.

4

PRINT TWO-ELECTRON INTEGRALS IN DEBUG FORMAT.

5

COMBINATION OF 1 AND 3.

6

COMBINATION OF 1 AND 4.

IOp(3/34)

DUMP OPTION. 0

NO DUMP.

1

CONTROL WORDS PRINTED (AS USUAL).

2 ADDITIONALLY, COMMON/B/ IS DUMPED AT THE BEGINNING OF EACH INTEGRAL LINK. 3 ADDITIONALLY, THE INTEGRALS ARE PRINTED (STANDARD FORMAT). IOp(3/35)


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LAST INTEGRAL DERIVATIVE LINK (No longer used in overlay 3). 0 WHATEVER LINK STARTS WRITING THE INTEGRAL DERIVATIVE FILE SHOULD ALSO CLOSE IT. DERIVATIVE N IS THE NUMBER OF THE LAST TWO-ELECTRON INTEGRAL PROGRAM. IOp(3/36)

Maximum order of multipoles to compute in L303: -1

None

0

Default (dipole).

1 2

Dipole. Quadrupole.

3

Octopole.

4

Hexadecapole.

00


10

Do not compute absolute overlaps.

20

Compute absolute overlap over contracted functions.

30

Compute absolute overlap over both contracted and over primitive functions.

IOp(3/37)

Whether to sort integrals in L320. 0

Default (No).

1

Yes.

2

No.

IOp(3/38)

Algorithm for 1e integrals:


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0

Default in 302, same as 1.

1

PRISM.

2

Rys.

00

Default in 308, same as 1.

10

PRISM.

20

Explicit spdf code.

IOp(3/39)

Initialization of force and force constant rwfs. 0 1

Initialize. Leave alone.

IOp(3/40)

Neglect of integrals: 0

keep all integrals.

1

neglect four center integrals.

2

neglect three center two-electron integrals as well.

3

neglect 2e integrals with diatomic differential overlap.

10

neglect three center one-electron integrals.

20

neglect 1e integrals with diatomic differential overlap.

30

Do only overlap and not other 1e integrals.

IOp(3/41)

Various semi-empirical methods. 0

No NDDO

1

NDDO


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00 Default use of NDDO beta parameters (arithmetic mean for indo parameters, geometric mean for NDDO/1 or read-in parameters). 10

Arithmetic mean in NDDO.

20 000

Geometric mean in NDDO. Default parameters (same as 5).

100 by

Read parameters for atomic numbers 1-18 in the order Scale (D20.12), followed

((HDiag(J,I),J=1,3),I=1,18) (Format 3D20.12), followed by ((Beta(J,I),J=1,3),I=1,18) 200

Read parameters from rwf.

300 400

Read parameters from chk. Original INDO/2 Beta and HDiag Parameters.

500

GNDDO/1 parametrization.

0000

Use STO-3G scale factors.

1000

Use Slater's rules scale factors.

00000

Default (unit overlap matrix).

10000

Use the unit matrix for the overlap.

20000

Use the real overlap matrix.

100000 Do CNDO/2. 200000 Do INDO/2. 300000 Do ZINDO/1. 400000 Do ZINDO/S. 1000000 Do Harris functional. 1100000 Do Harris functional scaling atomic densities for current charge and multiplicity. 1200000 First-order XC.


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1300000 Second-order XC (NYI). 1400000 Regular SCF with separate K, for testing. 1500000 J as usual but NDDO for K. IOp(3/42)

How to form NDDO core hamiltonian in L317: 0


1

Read the integrals sequentially.

2

Load all the integrals into memory.

IOp(3/43)

Solvent charge distribution to add to Hamiltonian: 0

None

1

Read charges and DBFs from input stream in input orientation

2

Read from RWF.

3

Read from Chk.

4

Same as 1.

5

Read charges and DBFs from input stream in standard orientation

10

Force units of Angstroms for coordinates.

20

Force units of Bohr for coordinates.

If negative, the perturbation is computed separately and stored in the third and fourth matrices in the core Hamiltonian rwf. IOp(3/44)

integral rejection using L318. 0

keep all integrals.

1

neglect four center transformed integrals.


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2

neglect four center and 3 center (ab|ac) integrals.

3

neglect four center and three center (0,0) integrals.

4

NDDO approximation -- no (ab|xx) and no

5

NDDO on 2e and V ints only -- T and S unchanged.

6

Do not transform 2e integrals, only 1e.

IOp(3/45)

Transformation matrix in L318. 0

use S**-1/2.

1 2

just orthogonalize functions on the same center. Use unit matrix (for debugging).

Order of multipoles in SCRF for L303. IOp(3/46)

Whether to abort the job if badbas detects an error: 0

Default (yes).

1

no.

2

yes

IOp(3/47)

Flags for use in PRISM and CalDFT throughout the program. -1

Force use of only the OS path for all calculations.

Bit flags: 0

If bit 0 is set (use AllowP array) then read in a list of allowed paths.

1

Use expanded matrix logic for PBC exact exchange.

2 Reverse choice of whether to precompute distance matrix during numerical quadrature.


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3

Skip consistency checks for XC quadrature

4

Do not do extra work to use cutoffs better, currently only affects CalDFT.

5

Reverse normal choice of diagonal/canonical sampling in Prism and PrmRaf. The

defaultdiagonal is only on vector machines. 6

Trace input and output using Linda/subprocess.

7

Force single matrix code in CPKS.

8

Force all near field in FMM.

9

Turn off vFMM.

10 11

Force square loops, currently only in PrismC. Force use of FoFCou, even if not doing FMM.

12 Reverse normal choice of Scat20 vs. replicated Fock matrices. Default is to use replicated matrices only on Fujitsu and NEC. 13

Turn off Schwartz during FMM/NFx calculations.

14

Turn off MP-based cutoffs in FF part of NFx.

15 16

Forbid use of gather/scatter digestion even for small numbers of density matrices. Reserved for more control of scatter/gather.

17

Turn on angular offsets in XC grid generation.

18

Use Mura radial grid instead of Euler-2 grid.

19

Do nuclear contribution in FoFCou even for non-PBC

20

Do not use special Coulomb algorithm in FoFCou.

21

Forbid use of FoFCou.

22

Turn off use of Sqrt(P) in density-based cutoffs.

23

No longer used.

24

Do allocation for parallel 2e integrals but run sequentially.


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25

Do allocation for parallel XC but run sequentially.

26

Make all atoms large in XC quadrature.

27

Make all shells large in XC quadrature.

28

Do not symmetry reduce grid points on unique atoms.

29

Turn on use of precomputed XC weights.

IOp(3/48)

Options for FMM: RRLLNNTTWW RR: LL:

Range (default 2) LMax (default from tolerance)

NN:

Number of levels (default 8)

TT:

Tolerance (default 18)

WW:

IWS (default 2).

IOp(3/49)

More options for FMM: 1

Indicates whether FMM can be used by FoFCou.

2

Uncontract all shell pairs.

4

Apply symmetry to derivative distributions (NYI).

8

Do not save as many multipole expansions as possible in memory.

16

Turn on FMM print.

32

Convert to sparse storage under FoFCou for testing.

64

Split primitives for better boxification.

128 Default UseUAB/Use 256.


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256 UseUAB, if 128 set. 512 Turn off parallelism in FMM (does not use parallel logic). 1024 Set up for parallel FMM but run loops sequentially. 2048 Do not default to FMM. 4096 Force FMM on. 8192 Set by PsmSet to indicate whether the NAtoms test for defaulting FMM was passed. IOp(3/51)

Parameters for NF exchange and box length (MMMMNN): 00

no NFx

NN

NFx range NN (R+n with n=NN-1).

0000xx Bohr).

Default box length, based on geometry (but minimum for molecules 3.0

MMMMxx Box length MMMM/1000 Bohr. IOp(3/52)

Turn off normal evaluation of ECP integrals. 0

Default: if needed, ECP integrals are evaulated in L302.

1

Old routines will be used, so L302 does not do ECP ints.

IOp(3/53)

Accuracy in ECP integral evaluation: 0

Default.

-1

No Cutoffs

N

10**-N.

IOp(3/54)


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Type of core density to use with ECPs: -1

None

0

Default (None)

1

Non-relativistic

2

Relativistic

IOp(3/55)

Use of sparse storage: N<-100

Yes, cutoff 5 x 10 ** (N+100)

-3 -2

Yes, intermediate accuracy (5x10**-7) Yes, crude accuracy (5x10**-5)

-1

Yes, default accuracy (10**-10).

0

No

N

Yes, cutoff 10**(-N)

IOp(3/56)

Cutoff for intermediate matrices during sparse operations: 0

100 times smaller than storage cutoff. N

10**(-N).

IOp(3/57)

No. of core electrons for Stuttgart/Dresden ECP's. IOp(3/58)

Cholesky control options. IOp(3/59)

Threshold for throwing avay eigenvectors of S:


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0

Default (10**-4) N

10**-N.

IOp(3/60)

Control of orthogonalization and simplification of ccp basis sets. 0

Default (1).

1

Orthogonalize and remove primitives with 0 coefficients.

2

Orthogonalize and remove primitives with 0 or small coefficients.

IOp(3/61)

Sparse Semiempirical Hamiltonian Cutoffs in L302: XX F(Mu,Lambda) atom--atom cutoff criterion (angstroms). Mu, Lambda are basis functions on different atoms. (Defaults to 15 angstroms). XX00 F(Mu,Nu) atom--atom cutoff criterion (angstroms) Mu, Nu are basis functions on the same atom. (Defaults to no F(Mu,Nu) cutoff). IOp(3/62)

Maximum allowed error in S over orthogonalized basis functions: 0

Default (10**-9). N

10**-(N).

IOp(3/63)

Debug option to test point charge FMM. 0

No.

1

Yes.

IOp(3/64)

Set value for ILSW derivative flag. Only active if IOp(3/39)=0.


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-2

Set to zero

-1

Set to -1.

0

Leave alone.

N

set to N.

IOp(3/65)

Number of k-points: -1

Just Gamma point.

N

About N points.

-N

Old logic for NRecip=N.

IOp(3/66)

Over-ride setting of NThInc in lineary dependence cutoff: -1

0

0

Don't change.

N

Set to N.

IOp(3/67)

Electric-field dependent functions: 0

Default (on if already present in basis read from rwf or chk, otherwise off).

1

No.

2

Yes, with standard values.

3

Yes, with read-in values.

IOp(3/70)

SCRF flag. 0

Default (1)


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1

Use defaults.

2

Read setting from checkpoint.

3

Read setting from the input stream.

4

Read setting from checkpoint and modify them by reading from the input stream.

5

Read from rwf.

0100

Flag for macroiterations (IPCM).

1000

SCI-PCM.

2000

D-PCM.

2100 2200

C-PCM. IEF-PCM.

2300

IVC-PCM

3000

Cramer/Truhlar solvation model.

4000

Onsager.

10000 Generate COSMOTHERMO output. IOp(3/71)

IDeriv level flag (for SCRF setup). IOp(3/72)

Solvent type flag (for SCRF setup). IOp(3/73)

ONIOM system flag (for SCRF setup). IOp(3/74)

Type of exchange and correlation potentials: -24

O3LYP.


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-23

HCTH407.

-22

HCTH147.

-21

B97-2.

-20

B97-1.

-19

HCTH93.

-18

B98.

-17

B1B95.

-16

BA3PBE.

-15 -14

BA1PBE. PBE3PBE.

-13

PBE1PBE

-12

mPW3PBE.

-11

mPW1PBE.

-10

mPW1LYP.

-9

LG1LYP.

-8

B1LYP.

-7

mPW91PW91.

-6

Becke3 with Perdew 91 correlation.

-5

Becke3 using VWN/LYP for correlation.

-4 -3

Becke 3 with Perdew 86 correlation. Becke "Half and Half" with LYP/VWN correlation.

-2

Becke "Half and Half": 0.5 HF + 0.5 LSD

-1

Do only coulomb part; skip exchange-correlation.


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00


00

No correlation.

01

Vosko-Wilk-Nusair method 5 correlation.

02

Lee-Yang-Parr correlation.

03

Perdew 81 correlation.

04

Perdew 81 + Perdew 86 correlation.

05

VWN 80 (LSD) correlation

06

VWN 80 (LSD) + Perdew 86 correlation

07 08

OS1 correlation PW91

09

PBE

10

VSXC

11

Bc96

18

VWN5+P86

19

LYP+VWN5 for scaling

20

KCIS

100

Hartree-Fock exchange.

200

Hartree-Fock-Slater exchange (Alpha = 2/3).

300

X-alpha exchange (alpha= 0.7)

400 500

Becke 1988 exchange. LG exchange.

600

PW91 exchange

700

Gill 96 exchange


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800

PW86 exchange

900

mPW exchange

1000

PBE exchange

1100

BA exchange

1200

VSXC exchange

So 100 is Hartree-Fock, 200 is Hartree-Fock-Slater, 205 is Local Spin Density, and 402 is BLYP. IOp(3/75)

Number of radial and angular points in numerical integration for DFT: 0

Use a special grid designed for efficiency (default).

IIIJJJ

III radial points, JJJ angular points.

IOp(3/76)

Mixing of HF and DFT. -10

O3LYP coefficients.

-9

B97-2 coefficients.

-8

B97-1 coefficients.

-7

HCTH coefficints.

-6

B98 coefficients.

-5

mPW91PW91 coefficients, same as B1B95.

-4

Becke 3 coefficients: aLSD + (1-a)HF + b(dBx) + VWN + c(LYP-VWN), with a=0.8 b=0.72 c=0.81. Note that Becke actually used Perdew correlation rather than LYP. -3

Becke "Half and Half" 0.5 HF + 0.5 Xc + Corr

-2

Coefficients of 0 and 0 (no exchange).

-1

Coefficients of 0.0 and 1.0 for DFT and HF, respectively.


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0

Default: pure HF, DFT or mixed in accord with IOp(3/76)

MMMMMNNNNN HF exchange.

Mixture of MMMM/10000 DFT exchange and NNNNN/10000

IOp(3/77)

Mixing of local and non-local exchange: -1

0 for both.

0

Default (coefficients of 1 and zero as determined by IOp(3/42)

MMMMMNNNNN MMMMM/10000 non-local plus NNNNN/10000 local. Sign is applied to the local term. IOp(3/78)

Mixing of local and non-local correlation: -1

0 for both.

0

Default (coefficients of 1 and zero as determined by IOp(3/42)

MMMMMNNNNN MMMMM/10000 non-local plus NNNNN/10000 local. Sign is applied to the local term. In L510, 1 to set up for CAS-MP2 or 2 to do spin-orbit calculation. IOp(3/79)

Range cutoff in Becke weights. 0

Default (SS weights)

-1

Use SS weights.

-2

Use Becke weights with default cutoff of 30 au.

-3

Use Savin weights.

-M<-3 Use SS weights with XCal = M/1000. N

Use Becke weights with cutoff N Bohr.

IOp(3/80)


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Range for microbatching in DFT. Negative to turn off screening of basis functions and grid points. 1000000000 turns of microbatching logic. IOp(3/81)

Frequency-dependence (if any) for XC functional. 0 Default (same as 1). 1

None (static limit).

2 Also static limit, but returning zero for imaginary response contributions, for debugging. 3

Gross-Kohn form.

IOp(3/82)

Fitting density basis set for Coulomb in DFT. -1

None.

0

Default (-1).

N

Same numbering of basis sets as for AO basis, including

7=General basis. See comments for IOp(3/5) and IOp(3/6) 28=Generate automatically from AO basis. IOp(3/83)

Equivalent of IOp(3/6) for density basis. For auto-generated basis sets: -1

Keep all generated functions.

0 Keep all functions with angular momentum up to MaxTyp+1, where MaxTyp is the highest AO angular momentum. N

Discard functions with L>=N.

IOp(3/84)

Equivalent of IOp(3/7) for density basis. For auto-generated basis sets: 0

Default (22)


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1

Use all products of AOs.

2

Use only AO primitives squared in fititing basis.

10

Do not split shells

20

Split F and higher shells away from S=P=D.

IOp(3/85)

Pure vs. Cartesian functions in density basis. 0

Default (pure for read-in basis).

1

Pure.

2

Cartesian.

IOp(3/86)

Discard basis functions based on angular momentum: 0

No.

N

Discard basis functions with angular momentum >= N.

IOp(3/87)

Discard density basis functions based on angular momentum: 0

No.

N

Discard density basis functions with angular momentum >= N.

IOp(3/88)

Modification of internally stored density basis. 0

None.

1

Read in general basis data in addition to setting up a standard basis.

10

Massage the data in Common /B/ and Common /Mol/.

100 Add ghost atoms to /B/ so that every shell is on a separate center. This is also done if requested in IOp(3/10).


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1000 Split S=P density basis shells into separate S and P shells. 2000 Do not split S=P density shells. 10000 Split S=P=D=... density shells into S=P, D, F, ... 20000 Do not split density S=P=D... shells. IOp(3/89)

Set up for density fitting. 0 Default (102 if a fitting set has been included and pure DFT is being used, 1 otherwise). 1

Do not use density fits.

2

Use fits, forming Z = modified A^-1.

3

Use fits, solving iterative with stored A.

4 Use fits, solving iterative with direct products, with A formed to generate preconditioning. 5

Iterative, no formation of A.

6

Form A' over neutral distributions via multiplies by A.

7

Form A' over neutral distributions via direct products.

1xx

Form inverse matrix once.

2xx

Solve iteratively with no preconditioning

3xx

Solve iteratively with diagonal preconditioning.

4xx

Solve iteratively with symmetric block-diagonal preconditioning.

5xx

Solve iteratively with non-symmetric block-diagonal preconditioning.

6xx

Solve non-iterative using precomputed A'^-1.

1xxx Put all functions into a single block in forming the preconditioning matrix. IOp(3/90)


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Thresholds for density fitting MMNN 10**(-MM) on iterative solution, default MM=09. 10**(-NN) on generalized inverse, default NN=06. IOp(3/91)

Scalar relativistic core Hamiltonian: 0

Default (1)

1

Non-relativistic.

2 3

RESC. Douglass-Kroll-Hess 0th order.

4

Douglass-Kroll-Hess 2nd order.

IOp(3/92)

Whether read-in basis sets are in terms of normalized primitives? 0

Default (12).

1

AO coefficients are for raw primitives.

2

AOs have normalization as for AOs.

3

AOs have J-normalization.

10

DBF coefficients are for raw primitives.

20

DBFs have normalization as for AOs.

30

DBFs have J-normalization.

IOp(3/93)

Nuclear charge distribution: 0

Default (1, unless scalar relativistic)


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1

Point nuclei

2

Single s Gaussians using formula of Quiney et. al

3

Very tight single s Gaussians, for debugging.

4

Same as 2 but exponents are 100x smaller, for debugging.

10x Include nuclear charge distributions in DBF set. Mxxx Use method M to handle nuclear charges during density fitting. IOp(3/94)

Range of PBC cells in Bohr. 0 default (100). N N Bohr. -M

Multiply usual range by M.

IOp(3/95)

Minimum number of PBC cells. -N

At least N cells in each direction.

0

Based on range estimate (IOp(3/94)).

N

At least N cells total.

IOp(3/96)

Number of PBC cells for DFT: 0 N

As many as look significant. At least N.

IOp(3/97)

Number of PBC cells for exact exchange: 0

As many as look significant.


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N

At least N.

IOp(3/98)

Maximum number of density matrices in PBC. 0

Default, based on number of cells having overlap with cell 0.

N

No more than N matrices.

IOp(3/99)

Whether to set up precomputed quadrature grid in L302: 0

Default (2 if doing DFT, -1 otherwise).

-1

No

1

Yes, storing only grid parameter

2

Yes, storing grid parameters and weights.

3

Yes, storing grid parameters, weights, and point coordinates.

IOp(3/100)

Minimum Number of PBC cells for PBC-MP2 0

Same as for HF exchange. N

N.

IOp(3/101)

Maximum range of cells -N

No more than N in each direction

0

No limit.

N

No more than N total.

IOp(3/102)


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Number of density fittings solutions to save from previous SCF iterations. Default is 6 (using 5 previous solutions plus the current right-hand side to generate the initial guess). Negative to use projected equations rather than least-squares. IOp(3/103)

Maximum number of vectors allowed in expansion space during iterative density fitting. Default is Max(NDBF/2,1000). IOp(3/104)

Maximum number of iterations during iterative density fitting. Default is Max((1000,NDBF+100). IOp(3/105)

Re-use of PBC cell data. 0

Default (re-use if present).

1

Reuse.

2

Do not reuse.

3

Read from chk file.

IOp(3/106)

Override default number of atoms threshold for turning on FMM (for debugging). This number is scaled up appropriately if symmetry is in use, to compensate for the loss of some symmetry with FMM. 0

Default (60)

N

N atoms for the C1 case.

Overlay 4 5 6 7 8 9 10 11 13 14 15 16 17 18 19 20 21 22 23 24 25 26 28 29 31 33 34 35 36 37 38 43 44 45 46 47 48 60 61 62 63 64 65 66 67 68 69 71 72 80 81 82 110 IOp(4/5)

Type of guess:


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0 Default. This uses the Harris functional unless atoms heavier than Xe are present, in which case Huckel is used. 1

Read guess from the checkpoint file.

2 3

Guess from model Hamiltonian, chosen via IOp(11). Huckel guess (only valid for NDDO-type methods).

4

Projected ZDO guess.

5 Renormalize and orthogonalize the coefficients which are currently on the readwrite files. 6

Renormalize and orthogonalize intermediate SCF results which are on the RWF.

7 Read intermediate SCF results which are on the checkpoint file. 8 Read generalized density specified by IOp(38) from the chk file & generate natural orbitals from it. 9 Read generalized density specified by IOp(38) from the rwf file & generate natural orbitals from it. 100 Convert Guess=Check to Guess=Restart or to generating guess depending on what if anything is on the checkpoint file. 1000 Use the simultaneous optimization recipe: S**-0.5 * V. 00000 Default (1 for PBC without alter, otherwise 2). 10000 Re-use Fock matrices instead of orbitals. 20000 Re-use orbitals not Fock matrices. Note that variable IGuess here has 4,3,2,1 corresponding to 1,2,3,4 above. IGuess values of 10-14 are generated internally and are the sparse versions of 0 and 5-8. IOp(4/6)

FORCED PROJECTION WHEN GUESS IS READ FROM CARDS (401). 0

FORCE PROJECTED GUESS, EVEN WHEN BASES ARE IDENTICAL.

1

FORCE PROJECTED GUESS, EVEN WHEN BASES ARE IDENTICAL.


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2

SUPPRESS PROJECTION.

00

Default orthogonalization (perform)

10

Schmidt orthogonalize guess orbitals.

20

Suppress orthogonalization.

000 Default MO checking (yes). 100 Check MOs for othornormality. 200 Don't check MOs for othornormality. IOp(4/7)

SCF CONSTRAINTS (401,402,403). -1 Ignore ILSW and determine on the fly. 0

USE ILSW TO DETERMINE.

1

REAL RHF.

2

REAL UHF.

3

COMPLEX RHF.

4

COMPLEX UHF.

5

COMPLEX, BUT USE ILSW TO DECIDE WHETHER RHF/UHF.

6

REAL ROHF.

IOp(4/8)

ALTERATION OF CONFIGURATION (401). 0

DO NOT ALTER CONFIGURATION.

1 READ IN PAIRS OF INTEGERS in free format INDICATING WHICH PAIRS OF MO'S ARE TO BE INTERCHANGED. PAIRS ARE READ UNTIL A BLANK CARD IS ENCOUNTERED. 2

Read in a permutation of the orbitals.


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10

READ ALTERATION INFORMATION FROM THE READ-WRITE FILE.

100 Use alpha orbitals for guess for both alpha and beta. NOTE IF THE CONFIGURATION IS ALTERED ON AN OPEN SHELL SYSTEM, TWO SETS OF DATA DESCRIBED ABOVE WILL BE EXPECTED, FIRST FOR ALPHA, SECOND FORAS BETA. IOp(4/9)

SCF symmetry control (401). 0

Default, same as 104

1 Read groups of irreducable representations to combine in the SCF. These are read before any 2

orbitals and before alteration commands. Use no symmetry in the SCF.

3

Pick up the symmetry mixing information from the Alteration read-write file.

4 use the full abelian point group, as represented by the symmetry adapted basis functions produced by link 301. Initial guess orbital symmetries are assigned. 5

(Use symmetry in SCF if possible, but do not assign initial guess abelian

symmetries). 10 Localize all occupied orbitals together and all virtual orbitals together 20

Localize the orbitals within the selected or defaulted symmetry.

100

Assign orbital symmetries for printing in full symmetry.

200

Do not assign orbital symmetries in full symmetry.

1000 Force the guess orbitals to have the Abelian symmetry. This option can cause the symmetry adapted basis function common blocks to be modified. IOp(4/10)

Orbitals to mix to form complex guess (401). 0

Mix the HOMO with the LUMO.


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1 Read from cards (2I3) pairs of integers indicating which pairs of orbitals are to be mixed. Reading is terminated by a blank card. NOTE THE SAME CONSIDERATIONS FOR OPEN SHELL SYSTEMS WHICH APPLIED IN IOp(8) APPLY HERE, ALSO. IOp(4/11)

Type of Guess (401): For iterative ZDO Guess: -1

Force old path using old Huckel.

0

Best available (6,4 in order of preference).

1

Old Huckel.

2

CNDO.

3

INDO.

4

New Huckel.

5

Iterative extended Huckel.

6diagonalization Harris, converted guess: to IGuess=3 and IZDO=3 here. For unprojected single 0


1

Use bare core matrix.

2

Dress core Hamiltonian with QEq-based density.

3

Use Harris Functional.

000 Default, same as 2. 100 Use SG1 and 10^-6 accuracy in Harris guess 200 Use FineGrid and 10^-8 in Harris functional. 300 Use UltraFine and 10^-8 in Harris functional.


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400 Use user's IRadAn and 10^-8 in Harris functional. 500 Use (199,974) and 10^-12 in Harris functional. 1000 Save energy in Gen(43) for Harris functional. n0000 Force IDoV=n in HarFok. MMMM00000

Use functional MMMM

IOp(4/13)

MIXING OF ORBITALS (401). 0

NO MIXING.

1 LUMOTHAT = LUMO + HOMO (ALPHA) AND LUMOBOTH = LUMO - HOMO (BETA). NOTE THIS WILL USUALLY DESTROY SPACIAL AND ALPHA/BETA SYMMETRY. THE MIXING IS DONE AFTER ANY ALTERATIONS. IOp(4/14)

Reading of specific orbitals (401). 0

No.

1 Yes. For alpha orbitals, read one card with the format for the orbitals, followed by zero or more sets of IVec (I5) -- vector to replace. If IVec is -1, all NBasis vectors follow. (Vector(I),I=1,NBasis) -- vector in the specified format. Input is terminated by IVec=0. For beta orbitals, the same format as for alpha is used. Note that if alter is also specified, the replacements are read before the corresponding alterations (thus the order is alpha orbitals, alpha alterations, beta orbitals, beta alterations). IOp(4/15)

Spin-state for initial guess (401). 0

Use multiplicity in /Mol/.

N Use multiplicity N. This is useful for generating guesses for open-shell singlets or unusual spin states involving orthogonal orbitals by treating them as high-spin in the guess (which only does UHF). IOp(4/16)


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Whether to translate basis functions of read in guess (401). 0


1

Use the basis functions as is.

2

Translate to the current atomic coordinates.

3 Translate to the current atomic coordinates, and determine an overall rotation to provide to the read- in orbitals. IOp(4/17)

Number of open-shell orbitals (not electrons) in 402. 0

#open electrons. N N.

Number of electrons in the CAS space. IOp(4/18)

Number of orbitals in CI in 402. Default is number of open shells. L405: Number of orbitals in the CAS space. CIOp(4/19)

L402: Spin change in CI (default based on multiplicity). L405: Trucation level for excitations -- default full CAS. IOp(4/20)

Type of model (402): (This is also tested in 401 to see whether atomic number greater than 102 are special flags). 0

Default (AM1).

1

CNDO.

2

INDO.

3

MINDO/3.


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4

MNDO.

5

AM1.

IOp(4/21)

SCF type (402). 0 Default (no Pulay, no Camp-King, 3/4 point on unless Pulay or Camp-King, use pseudodiagonalization). 1

3/4.

2

No 3/4.

10

No Pulay (DIIS).

20

Pulay.

100

No Camp-King.

200

Camp-King.

1000 Use pseudo-diagonalization. 2000 No pseudo-diagonalization. Flags for MCSCF (L405): 1 Read options from input stream. 10

Use slater determinants.

100

Just list configurations.

1000

Use determinant basis with Sz=b/2.

10000 Write unformatted file (NDATA) of symbolic matrix elements. 100000 Write formatted file of symbolic matrix elements. IOp(4/22)

Derivatives? (402). 0

No.


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1

Yes.

2

2nd derivatives.

12

Restart 2nd derivatives.

100 Do 1st derivatives analytically if possible. More flags for MCSCF: 1

IFlag2

IOp(4/23)

Number of iterations (402, 403). 0

Default.

N N. NDiag in L405. IOp(4/24)

Whether to update orbitals, eigenvalues, /Mol/, and ILSW on the rwf (402). 0

Default (don't update).

1

Update. (For straight semiempirical calculations).

2

Don't update. (For Opt=MNDOFC).

3

Update, but don't convert from Lowdin orbitals.

10

Update second force array instead of first. (For Opt=MNDOFC).

NRow in L405. IOp(4/25)

Wavefunction (402). 0

Default (Same as 1).

1

Single determinant, RHF/UHF from IOp(5).

2

ROHF (NYI).


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3

Biradical 1/2 CI (only for MINDO3,MNDO,AM1).

4

Closed-shell 1/3 CI (only for MINDO3,MNDO,AM1).

5

General CI, using specified orbitals.

-N

General CI, with N microstates read in.10 binary switches in L405.

IOp(4/26)

Whether to mix orbitals in generated guess density: 0

No

-3 Yes, mix valence occupieds with 0.05 au (according to ZDO) of the HOMO & virtuals within 0.15 au. -2

Yes, mix valence orbitals and an equal number of virtuals.

-1

Yes, mix all equally.

N

Equal occupations of the lowest N virtuals and high N occupieds.

IOp(4/28)

SCF Convergence (10**-N, default 10**-7). IOp(4/29)

NC in L405. IOp(4/31)

Root to solve for in CI (402) (Default is 1). IOp(4/33)

PRINTING OF GUESS. 0

NO PRINTING.

1

PRINT THE MO COEFFICIENTS.

2

PRINT EVERYTHING.


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IOp(4/34)

DUMP OPTION. 0

NO DUMP.

1

TURN ON ALL POSSIBLE PRINTING.

IOp(4/35)

Overlap matrix. 0

Default (copy on disk is used).

1

Overlap assumed to be unity.

2

Copy on disk is used.

IOp(4/36)

ZIndo reformating. 0

No.

1

Yes, reformat ZIndo integrals and wfn into rwf.

IOp(4/37)

Selection of old MNDO parameters in L402: 0

Defaults.

1

Old Si parameters.

2

Old S parameters.

IOp(4/38)

Generalized density to use for natural orbitals: N

Density number N.

IOp(4/43)

IDiEij = Switch for direct matel calculation.


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0 For normal route, with all matels calculated here and stored on disk. Configs printed as normal. 1 For direct route. Eij's calculated here and stored on disk. A flag is automatically sent to L510 to in tella it to compute the remaining atels directly. This type of computation can only be done CAS comp. Also L510 must use Lanczos. The configurations will not be listed unless see below. 2 As option 1, but all configurations are printed. This will be the only way to print configs in a direct matel calc, since there can be many thousands in a large CAS. IOp(4/44)

1in MC-SCF Prepare input for Mp2 implies IOp(21)=10 Slater Det. option generates data for use generation of zeroth order H note: for b=0 ie no unpaired spins forces use of Clifford Algebra Spinors instead of simple determinants c2IOp(4/45)

Ipairs = number of GVB pairs in GVBCAS. 0

Default. No pairs, normal CAS calculation.

n There are n pairs: 2*n extra orbitals and electrons will be added into the active space later. L405 performs a CAS on the inner space, and sets up L510 to compute extra matels etc. implicitly. This is a normal GVBCAS calculation. -n There are n pairs: 2*n orbitals and electrons of the specified CAS are to be considered to be GVB type orbitals when generating configs / matels. L510 will execute normally. This occupies as much space as a full CAS in this link, but is smaller subsequently. This is the GVBCAS test mode. IOp(4/46)

CI basis in CASSCF: 1

Hartree-Waller functions for singlets


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2

Hartree-Waller functions for triplets

3

Slater Determinants

10

Write SME on disk

IOp(4/47)

Convert to sparse storage after generating guess. -1

No, use the Lewis dot structure to generate a sparse guess directly.

0

Default (-1 if sparse is turned on)

N

Yes. Use threshold 10**-N.

IOp(4/48)

Whether to do (sparse) Conjugate Gradient methods in 402: 0

No.

1

Yes. Use Lewis dot structure guess density.

2

Yes. Use diagonal guess density.

IOp(4/60-62) IOp(60-62)

Over-ride standard values of IRadAn, IRanWt, and IRanGd. IOp(4/63)

Flags for which terms to include in MM energy: 0

Default (111111)

1

Turn on all terms, r**-1 Coulomb.

2

Turn on all terms, r**-2 Coulomb.

10

Turn on non-bonded terms.

100

Turn on inversions/improper torsions


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1000

Turn on torsions.

10000

Turn on angle bending.

100000 Turn on bond stretches. IOp(4/64)

Cutoff for MM non-bonded term. 0

Default (no cutoff). N

10**-N.

IOp(4/65)

Tighten the zero thresholds as the SCF calculation proceeds. 0

Default: Yes, initial threshold 5x10-5.

1

No variable thresholds.

N

N

10**-N. Yes, initial threshold 10**(-N)

N<-100 Yes, initial threshold 5 x 10 ** (N+100) IOp(4/66)

Dielectric constant to be used in MM calculations. 0

Eps = 1.0.

N

Eps = N / 1000.

IOp(4/67)

Whether to use QEq to assign MM charges. 0

Default (211 if UFF, 2 otherwise, 1==> 221)

1

Do QEq.

2

Don't do QEq.


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00

Default (20)

10

Do for atoms which were not explicitly typed.

20

Do for all atoms regardless of typing.

000 Default (200) 100 Do for atoms which have charge specified or defaulted to 0. 200 Do for all atoms regardless of initial charge. IOp(4/68)

Convergence criterion for microiterations in L402: 0

Default. N 10**(-N).

IOp(4/69)

Whether to do a new additional guess in addition to reading orbitals from the rwf: 0

Default: yes if no Guess=Alter, Harris guess, and not a small geometry step.

1

Do the extra guess regardless.

2

Do not do the extra guess.

3

Do the extra guess and store as the initial Fock matrix.

00

Default (10 for PBC, 20 otherwise).

10

Save the Harris guess as an initial Fock matrix.

20

Just generate orbitals from the Harris guess.

IOp(4/71)

Write out AM1 integrals in 402 0/1 No/Yes. IOp(4/72)

Irreps to keep in MCSCF CI-wavefunction.


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0

All

IJKLMNOP

List of up to 8 irrep numbers to include.

IOp(4/80)

The maximum conjugate gradient step size (MMNN) 0000

No maximum step size

MMNN

Step size of MM.NN

IOp(4/81)

Sparse SCF Parameters MM Maximum number of SCF DIIS cycles. (MM=00 defaults to 20 cycles, MM=01 turns DIIS off) NN00 on the

F(Mu,Nu) atom--atom cutoff criterion (angstroms) Mu, Nu are basis functions same atom. (defaults to no F(Mu,Nu) cutoff).

PP0000 F(Mu,Lambda) atom--atom cutoff criterion (angstroms) Mu, Lambda are basis functions on different atoms. (defaults to 15 angstroms). IOp(4/82)

Conjugate-Gradient Parameters MM

Maximum Number of CG cycles per SCF iteration. (defaults to 4 CG cycles).

NN00 cycles).

Maximum Number of purification cycles per CG iteration. (defaults to 3

00000

Don't use CG DIIS

10000

Use CG DIIS.

000000

Polak-Ribiere CG minimization

100000

Fletcher-Reeves CG minimization

0000000 Use diagonal preconditioning in Conjugate-Gradient.


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1000000 No preconditioning. IOp(4/110)

Scaling of rigid fragment steps during microiterations.

Overlay 5 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 45 47 48 49 50 51 52 53 55 56 57 58 59 60 61 62 63 64 65 70 71 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 IOp(5/5)

Direct SCF control (L502, L508). 0


1

Read the integrals off disk.

2

Compute 2e integrals.

3

Compute 2e integrals and store in-core.

4

Compute 2e integrals and forbid in-core.

NNNNNx

Use option NNNNN in control of 2e integral calculation.

0000000

Default -- incremental Fock matrix formation only for direct SCF.

1000000

Form full Fock matrix every time.

2000000

Form delta-F each iteration -- only in L502.

L510: Direct MCSCF control (L510).(How to Obtain the Integrals) 0

Incore or Direct(FoFDir) according to available Memory.

1

Read the integrals off disk OR Incore (Acording to Memory)

2

Compute 2e integrals(Using FoFDir).

3

Compute 2e integrals (Use TrnDir + FoFDir = 4 Can. Calcs).


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4

Force FoFDir, forbidding incore

5

Force conventional

6

Something obsolete

NNNNNx use option NNNNN in control of 2e integral calculation. NNNNN=ICntrl with values as below.: ICntrl = Algorithm control: 0

Default for MCSCF is (1522).

1

Force Rys only.

2

Force HGP only. The default for first derivatives.

3

HGP sp, Rys df (for debugging).

4

HGP spd, Rys f.

5

HGP d, Rys f (no sp done here at all).

6

HGP df (no sp done here at all).

7

BraKet only. The default for integrals or second derivatives.

8 10

BraKet up to L=8, rest not done here. No cutoffs.

20

Cutoffs for 10**-10 accuracy.

30

Cutoffs for high accuracy.

40

Sleazy (10**-6) Cutoffs.

100 Do not compute operator matrices. 200 Compute SCF Fock matrices. 300 Compute CIS operators 400 Compute WTilda terms. 500 GVB: DA==>FJ,FK.


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600 Compute regular integrals and load into R03, in canonical form if IOpcl=0 and square form if IOpcl=1. NMatS is used as the dimension of R0 if IOpcl=1. 700 Compute raffenetti integrals: IOpCl=0 IOpCl=1

Load R1. Load R1 and R2.

IOpCl=2

Load R1 and R03.

IOpCl=3

Load R1, R2, and R03.

IOpCl=4 Load R2 and R03. 1000 Do not compute forces. 2000 Compute forces. 3000 4000

Make Make derivative derivative Fock Fock matrices matrices and form contributions to polarizability derivatives (ie 6 sets of forces will be returned in FXYZ, and 3 extra sets of densities must be supplied in PA,B).

5000

Compute forces using including CIS 2PDM terms.

10000

Compute second derivatives.

0000000 Default -- incremental Fock matrix formation only for direct SCF. 1000000 Form full Fock matrix every time. 2000000 Form delta-F each iteration -- only in L502. IOp(5/6)

Convergence (RMS density except in L506 (SQCDF), L508(rms rotation gradient), and L510 (Energy)). 0

10**-8, except 10**-7 for PBC.

N 10**-N. L510: CONVERGENCE CRITERIUM (ACC) FOR THE ENERGY IN THE MCSCF 0 N

Acc = 10**(-8) Acc = 10**(-N)


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IOp(5/7)

Maximum number of iterations. 0

128, except 512 in L503 and L508.

L510: MAXIMUM NUMBER OF ITERATIONS TO BE DONE (MaxIt) 0 -1

MaxIt=64 (Default Value) N

MaxIt=N It does only a CI calculation. Options other than the standard SCF ones:

IOp(5/8)

SELECTION OF THE PROCEDURE OF DIRECT MINIMIZATION (L503). 0

STEEPEST DESCENT WITH SEARCH PARAMETERS DEFAULT

1

STEEPEST DESCENT WITH SEARCH PARAMETERS READ (SEE BELOW)

2 CLASSICAL SCF (ROOTHAAN'S METHOD OF REPEATED DIAGONALIZATION 4

CONJUGATE GRADIENTS WITH SEARCH PARAMETERS DEFAULT

5

CONJUGATE GRADIENTS WITH SEARCH PARAMETERS READ: MAX. NUMBER OF SEARCH POINTS (I1) MIN. NUMBER OF SEARCH POINTS (I1) INITIAL STEPSIZE, TAU (G18.5) SCALING FACTOR FOR SUBSEQ. TAU (G20.5) Q (G20.5)

Search method (L508). 0

Default (123).

1

Steepest descent.

2

Scaled steepest descent.


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3

Quadratic convergence (after rotation gradient is sufficiently small).

00

Default linear search (full search).

10

Do a full linear search to locate a minimum.

20

Do a linear search only if the energy goes up after the initial step.

000

Default handling of wrong curvature (switch direction).

100

Reverse direction if curvature in NR step direction is wrong.

200

Take pure NR steps, even if curvature is wrong.

Flags for L510: 1 10

IRdF2, read damping coefficients. IFrzCI, freeze CI coefficients after 1st iteration.

100

Read unformatted symbolic matrix elements from NDATA instead of rwf.

1000

Read in damping factors from cards.

10000 Use Levy damping. 1000

Read Fock matrix restriction matrix.

IOp(5/9)

SWITCH TO CLASSICAL SCF AFTER DENSITY MATRIX HAS ACHIEVED A CERTAIN CONVERGENCY (L503 only). 0

NO

1

YES, CRITERION DEFAULT 10(**-3)

2

YES, CRITERION READ IN (FORMAT G16.10)

Number of pair iterations (L504, L506). -1 None; coefficients are frozen at initial values (L504: causes coefficients to be read in in order 11 12 22).


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0

5.

L510: IOp(5/10)

IVShft Level shifting: -N

Dynamic level shifting to achieve a gap of -0.001*N

-2

Dynamic level shift to a default goal (same as -200)

-1

No level shifting.

0 Default: -200 for diagonalization calculations, -1 for sparse diagonalization replacements, N

and if energy DIIS is turned on. Shift by 0.001*N

IOp(5/11)

3 and 4 Point Density extrapolation control (L501,L502, L503 has only 4 point, L505). 0 BOTH 3-POINT & 4-POINT EXTRAPOLATION PERFORMED WHEN APPLICABLE. 1 THREE-POINT EXTRAPOLATION IS INHIBITED, BUT THE PROGRAM WILL STILL PERFORM FOUR-POINT EXTRAPOLATION WHEN POSSIBLE. (IE. DISABLED). IOp(5/12)

Whether to allocate only two N**2 arrays for RHF: 0

Default (No).

1

Yes.

2

No.

Number of GVB pairs (L506). If non zero, the number of orbitals in each pair is read in format (30I2). Each pair consists of the highest available occupied from the guess (after high spin orbs are accounted for) and the lowest


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available virtuals. If <0, pair coefficients are read; otherwise standard initial values are used. IOp(5/13)

Action on convergence failure (L502): 0 Default (2). 1 Continue the run even on non-convergence. The ILSW flag for convergence failure is set. 2

Terminate on non-convergence.

L510: MCSCF flags: 2 Generate MOs using UHF natural orbitals. 10 IRdNLp.(Calculates directly Nact*(Nact+1)/2 Fock matrices by contracting the AO integrals with the Density matrices.-For testing purposes,turned on automatically in FoFDir100

INFC Number of Frozen Core Orbitals

XX000 IRdNT. Number of rows in an initial transformation of MO. (More input from cards See below) IOp(5/14)

Special functions in L502: 0

None.

1

Turn the current RHF run into a uhf run at the end of this link.

10

Terminate after computing the 2e terms at the first iteration.

20

Just recompute band structure from stored real-space Fock matrix.

100 ADMP, later cycles: transform the density from L121 before calculating the energy and Fock matrices. 200

ADMP, first cycle: use initial AO densities.

1000 Use Generalized energy-weighted density routines regardless.


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2000 Do not use GEW routines even for CP. 10000 Fit the converged density even if fitting is not in use during the SCF. Also redoes the fit at the end even if using fits during SCF. CONTROL OF ANNIHILATION OF SPIN CONTAMINANTS (L502). 0 CALCULATION IS PERFORMED (PROVIDED OF COURSE THAT ENOUGH SPACE EXISTS IN THE RW-FILES). 1

CALCULATION IS BYPASSED.

2 CALCULATION IS PERFORMED, CONTINGENT ON SPACE, AND THE SYSTEM RW-FILES FOR THE APPROPRIATE DENSITY MATRICES ARE UPDATED (USEFUL IF ONE WANTS A POPULATION ANALYSIS). REORDERING OF THE ORBITALS (MAINTAINING CONTINUITY OF THE WAVEFUNCTION ALONG THE SEARCH PATH, L503). 0

ON BESSEL CRITERION

1

ON STRONGER INDIVIDUAL-OVERLAP CRITERION

2 OFF L510: Flags for MCSCF: 1

Skip valence-valence Fock matrix elements.

10

Skip core-valence Fock matrix elements.

100

Skip valence-virtual Fock matrix elements.

1000

Skip core-valence Fock matrix elements.

10000 Use full diagonalization method rather than Lanczos. (Obsolete; use IOp(17)). 100000 State average density matrices. IOp(5/15)

Apply Abelian symmetry constraints on orbitals.


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0

Default (1 for L502, 2 for L501 and L506).

1

No.

2

Yes, keep occupation of each irrep the same as the initial guess.

3 Yes, keep overall wavefunction the same as the initial guess, but doing the minimal amount of orbital switching to accomplish this. 00

Default (use Abelian symmetry in diagonalization).

10

Use Abelian symmetry in diagonalization.

20

Do not use Abelian symmetry in diagonalization.

CONTROLS THE AUTOADJUSTMENT OF TAU (L503). 0 DONE 1

TAU IS KEPT FIXED

IOp(5/16)

Diagonalization method (L502): 0

Default (1 for full matrices, 4 for sparse).

-N

Pseudo-diagonalization with real diagonalization every Nth cycle.

1

DiagD.

2

KyDiag.

3

Pseudo-diagonalization whenever possible.

4

CGDMS.

5

PDM.

6

CEM.

7

Sign Matrix Method.

8

SNRDMS.


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1xx

Force formation of the Fock matrix using full storage.

2xx

Force formation of the Fock matrix using sparse storage.

INHIBIT PERFORMANCE OF MINIMIZATION OF ALTERNATE WAVEFUNCTION PROVIDED BY(L503). SECOND ORDER PROCEDURES 0

NO

1

YES

Selection of OCBSE vectors (L506). 0

By eigenvalue.

1 2

By energy least change. By orbital least change.

Lanczos starting vector in L510: -1

Read in eigenvector.(ILzVec=-1) See below

0

C(1) = 1.0

N

C(N) = 1.0

IOp(5/17)

CONDITION OFF-DIAGONAL TERMS OF THE Fock MATRIX (L503). SET TO ZERO IF Abs(F(I,J)).LE.FUZZY; DELETE COUPLING TERMS BETWEEN ALMOST DEGENERATE (DELTA E .LE. DEGEN) M.O. VECTORS 0

FUZZY=1.D-10, DEGEN=2.D-5

1

FUZZY AND DEGEN READ IN (2D20.14)

Selection of virtual orbitals (L506). 0

Virtuals obtained by diagonalization of hamiltonians.

1

Virtuals obtained by Schmidt orthogonalization to occupieds.

Use of symmetry (in L502 and L508) and linear equation convergence (in L508):


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0

Default (1032 for 502, 1012 for 508).

1

Choose LinEq convergence based on orbital gradient.

2

Always use tight convergence.

3

Tighten convergence by an extra factor of 10.

10 If 2E symmetry is on, symmetrize Fock matrices and require proper density matrix symmetry. 20 If 2E symmetry is on, replicate integrals so that density matrices and wavefunctions need not be symmetric. 30 If 2E symmetry is on, choose between replicating integrals and symmetrizing the Fock matrix based 40

on whether the current density matrix is symmetric. Same as 30 in 502 but 20 in 508.

100

Force the density matrix to have full symmetry at the first iteration.

200

Force the density matrix to have full symmetry at every iteration.

0000 Default (1000) 1000 If the density matrices pass the symmetry test, symmetrize them to ensure that they are exactly symmetric. 2000 Do not symmetrize the density matrices. L510: MCSCF flags. 0

Orthogonalize C,O,V by separate Lowdin, then Schmidt.

1

Lowdin orthogonalize C+O and V, then Schmidt.

2

Just schmidt.

5

Don't orthogonalize.

10

Don't use natural orbitals each iteration. Bad for 1st order method.

100

Use full 2nd order convergence.

200

2nd order iteration at end, in preparation for CPMCSCF.


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300

2nd order iteration using RFO type step + level shift.

400 Prepare for CPMCSCF(FREQ): Direct method with no storage of Hessian. Warning!! should be used only for large jobs where Hessian does not fit in memory. 500 2nd order iteration using RFO type step + level shift and prepare for non-direct CPMCSCF 10000

Attempt to control root flipping in CI.

100000

Read CI vector and use it every iteration.(IRdCIV)

1000000 Use full diagonalization method rather than Lanczos. 10000000 Use State Average density matrices.(the weights 8F10.8) 20000000 Do SA and prepare for SA-CPMCSCF. 30000000 Do SA and prepare for Gradient of Energy difference. 40000000 Do SA and prepare for SA Second Derivative Computation (terms involving 2nd order orbital rotation derivatives not included) IOp(5/18)

L502: Mixing when doing damping: -3 MO damping at all iterations. -2

Turn off damping.

-1

Dynamic selection of density damping based on band gap and DIIS error.

0

Default (-1 unless reoptimizing during Stable=Opt).

N

N/100 new density, (100-N)/100 old density.

L503: CUTOFF CRITERIA IN SYMMETRY DETERMINATION OF M.O.S. SYMMETRY IS DETERMINED IF LARGEST OFF-DIAGONAL M.O. FOCKMATRIX ELEMENT Abs(F(I,J)).GE.STHRS ELEMENTS Abs(F(I,J)).LE.SPAN ARE CONSIDERED TO BE ZERO 0

STHRS=1.D-4, SPAN=5.D-7


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1

STHRS AND SPAN READ IN (2D20.14)

Damping (L506) Maximum rotation gradient for Newton-Raphson in L508 (above this value, scaled steepest descent is used): 0 Default (1.d-2).

N

10**-N.

IOp(5/19)

Over-ride integral storage control (L501, L502, L506, L508): -1

Choose the best given amount of memory available.

0

2 if possible, otherwise 1.

1 Forbid in-core: force re-reading of integrals even if they fit in 2 buffers if conventional, do not convert to in-core if direct and enough memory for in-core is available. 2

Force allocation for 1 or 2 buffer case conventional case (VV.ne.IBuf2E).

3

Force Lower-triangular in-memory storage.

4 1x

Force Square in-memory storage. Save generated integrals on disk (file 610).

2x

Force computation of raff 1 and 2 integrals even for RHF.

3x

Do not save integrals (same as 0x).

PRINT F(1),T. (READ ONE CARD WITH START,END 2I2) (L503). 0

NO

1

YES

IOp(5/20)

Final non-DIIS iteration (L501, L502, L504). 0

Default (no).


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1

Yes, do a final unextrapolated diagonalization after convergence is reached.

2

No, just quit when extrapolated convergence is reached.

Orbital rotation control (L506). N

Rotations are turned on when SQCDF is below 10**(-N).

IOp(5/21)

DIIS error for density damping, maximum virtual mixing for MO damping: For density damping: 0

Default (Damp if error > 0.001)

N Damp if error > 10**-N For MO damping: 0 N

Default, no more than 1/3 virtual component for any occupied at each iteration. Maximum N/1000 virtual component.

ACTION IF OTEST DETECTS PROBLEMS (L503). 0

ABORT RUN VIA LNK1E.

1

CONTINUE RUN.

Extrapolation control in L506. MCSCF flags: 2

Generate MOs using UHF natural orbitals.

10

IRdNLp.

IOp(5/22)

Use of DIIS extrapolation (L501, L502, L504). 0 Default (1042) for calculations using diagonalization (2) for calculations using sparse diagonalization replacements. 1

No.


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2

Yes.

3

Yes, with Fermi broadening as well, deciding on the fly between the two forms.

4

Yes, with "pFON" version of Fermi broadening.

5

Yes, with "FON" version of Fermi broadening.

10

Regular DIIS

20

Energy-based mixing

30

Energy DIIS when DIIS error has increased significantly or is above threshold

40 Energy DIIS when DIIS error has increased significantly, otherwise, mixture of energy and commutator. 1xx

Use energy DIIS when commutator gives huge coefficients.

Nxxx Switch from energy to commutator when error is 10^(-N) in method 3; used (DIIS error/10^-N) for weight of energy DIIS in method 4. Mxxxx

Use print level M in DIIS.

Orbital mixing control in L506. IOp(5/23)

Flag for later points of an optimization, so that pair and hamiltonian information can be reused (L506, L509). 0

Read from input stream.

1

Read from rwf.

2

Read from chk.

IOp(5/24)

Orbital freezing (L506). 0

Optimize all orbitals.

1 Freeze all closed, high spin and first natural orbitals. Optimize only 2nd and higher naturals.


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IOp(5/25)

Rotation application (L506). 0

Default (exponentiate rotation angles).

1

Apply rotations sequentially.

IOp(5/26)

Type of calculation (L504). 3

3rd root of CAS(2,2)

2

Excited singlet as 2nd root of CAS(2,2).

1

GVB as CAS(2,2)

0

GVB(1/2)

-1

Orthogonal open-shell singlet.

-2

ROHF Triplet (a debugging option).

Number of hamiltonians to read in (L506). If zero, the unpaired orbitals are assumed to be high spin. If -1, an open-shell singlet is assumed. Closed/Open control for L511: 0

Default, closed for Multip=1.

1

Force closed shell, error if Multip>1.

2

Force UHF.

IOp(5/27)

Whether to do closed-shell calculation in L502. 0

Default (Yes, if mulitplicity 1).

1

No

2

Yes (used for RHF direct SCF).

IOp(5/28)


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L510: Root of CI to use in MCSCF (IState) 0

Defaults to Istate=1

-1

Read IState from cards (see below)

N

IState = N

IOp(5/29)

Use of rafinetti integrals during direct SCF. -1

All integrals done as Raffenetti.

0

Default: let FoFDir decide. It will never use Raffenetti for SCF.

1 All integrals are done as regular integrals. N Integrals with degree of contraction greater than or equal to N are done are regular integrals. IOp(5/30)

Whether to symmetrize final orbitals using abelian symmetry operations (L502, L505, not needed in L506). 0

Default (Yes).

1

Yes.

2

No.

IOp(5/31)

How many vectors to form at a time during microiterations in L508 (NYI) and L509: 0

Default (3 in L509). N

N.

IOp(5/32)

Sleazy SCF (L502, L510): 0

Default (No).


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1 Yes, use loose integral cutoffs, convergence on either energy or density and always do incremental Foc formation. 2

No.

3 4

Thresholds similar to DGauss for convergence and integrals. Yes, doing an inexpensive pass 0 and then full accuracy in pass 1.

5

Decide between 1 and 4 based on details of the calculation.

6 Do iterations with sleazy XC grid, then one iteration with next grid up. The default is CoarseGrid for iterations and SG1 for final energy. 00

No longer used.

N00

No longer used.

I000

Use approximation I, 0=normal 1=Linear approximation to Xc.

00000 Use general DBF logic only if the DBF rwf is present. 10000 Force use of 1c instead of general DBF logic. 20000 Force use of general DBF logic. IOp(5/33)

PRINT

IOp(33) PRINT OPTION.

0 ONLY SUMMARY RESULTS ARE PRINTED (WITH POSSIBLE CONTROL FROM THE 'NO- PRINT' OPTION). 1 THE EIGENVALUES AND THE M. O. COEFFICIENTS ARE PRINTED AT THE END OF THE SCF. 2PRINTED. SAME AS IOp(33)=1, BUT ADDITIONALLY THE DENSITY MATRIX IS 3

SAME AS IOp(33)=2, BUT AT THE END OF EACH ITERATION.

4

SAME AS IOp(33)=3, BUT ALL MATRIX TRANSACTIONS ARE PRINTED (BEWARE!!! MUCH OUTPUT EVEN ON SMALL MOLECULES.)


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IOp(5/34)

DUMP OPTION. REGULAR SYSTEM DEFAULTS APPLY HERE. IOp(5/35)

Whether basis is orthonormal (L501, L502). 0

Default (No).

1

Yes.

2

No.

IOp(5/36)

Whether to checkpoint after every SCF cycle. 0

Default (checkpoint only if direct).

1

Checkpoint.

2

Don't checkpoint.

IOp(5/37)

Frequency at which to do full Fock formation instead of incremental (L502). -1 0 N

Do not do incremental Fock formation. Default (every 20 for direct). Every Nth cycle.

IOp(5/38)

Whether to vary integral cutoffs during direct SCF: 0


1

No.

2

Yes, do integrals 3 digits more accurately than current convergence.

3 Yes, do integrals at same accuracy as convergence until final iteration, then 2 digits more accurately.


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4

Converge to 10**-5 with integrals good to 10**-6 first, then full convergence.

5

VarAcc allowed, decide based on details of problems.

6

VarAcc forbidded because of guess=read; allows different default actions for PBC.

IOp(5/39)

New On-Fly symbolic matrix element generator. REQUIRE 'NOFULLDIAG' Remember: the first digit indicating the type of function to be used, must be set. 1

Hartree-Waller functions for singlets

2

Hartree-Waller functions for triplets

3

Slater Determinants

xx0 Use cutoff = 10**(-xx) on integral value to exclude contributions. Default is DON'T EXCLUDE any integral yy000 Use cutoff = 10**(-yy) on the product Integr*DenMat. Default is DON'T EXCLUDE any integral 100000 Lanczos

Use sum of the first IState roots of a Reduced Hamiltonian as guess for

200000

Use IState-th root of a Reduced Hamiltonian as guess for Lanczos

300000 Save first IState roots on disk for Davidson (this option will automatically call Davidson instead of Lanczos) 1000000

Print S**2

2000000

Print S**2 and its orbital components

IOp(5/40)

Use of reaction field; only used now for Onsager and control of details of SCIPCM -N

Multipoles of order N, increment field in Gen(2-4)

0

No.

N

Multipoles of order N, store field in Gen(2-4)


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00000 Default (same as 10000). 10000 Update surface every iteration. 20000 Update surface every iteration in pass 1 only. 30000 Update surface on pass 2 iterations only. 40000 Same as 3, but re-use 1e matrix instead of surface terms. 50000 Update surface and restart DIIS when within 10**-2 of convergence. IOp(5/41)

Whether to converge on maximum density change as well or instead of RMS: 0 N

22. Maximum allowed change is 10**N larger than RMS.

-1 Maximum allowed changed is same as RMS (i.e., convergence only on maximum). -2

Converge only on RMS density change.

N0 Converge on energy to 10**(N)*RMS-density-accuracy Also control of iterative diagonalization in L510. L510: Davidson options. Option xx is used also by Lanczos if IOp(39)=10000n or 20000n xx Maximum dimension of reduced Hamiltonian used as guess Default=Min(NSec,50) yy00

Maximum dimension of iterative subspace. Default=60

zz0000

Number of vectors provided in input BEWARE !!! Davidson will execute zz updating per iteration. Default=IVEC

k000000 Reduction factor between number of guess vectors provided and number of vectors wanted at the end (1<=k<=9). WARNING !!! ratio (zz+k-1)/k must be equal to n, number specified in nroot=n. Default=1 (no reduction)


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ll0000000 Davidson iteration at which to scale back the number of vectors WARNING !!! For overflow reasons, value must be 0<=ll<=20 Default=0 IOp(5/42)

Number of orbitals to localize in L510 1

Localize all active orbitals

n

Localize first n (strongly occupied!) orbitals

IOp(5/43)

L509: Whether 5th order terms are treated explicitly 0

Default: set to 1

1

All 5th order terms are treated implicitly

2

(Debug option) 5th order GG and WG terms are explicitly computed in L715

L510: DFT corrections to MCSCF on last iteration 0

No

1 Yes. Uses MC-SCF density to compute B88 + LYP energy (These are hard-wired since they were the only choices that gave sensible results) 2

Replaces diagonal elements of MC-SCF CI with B88 + LYP energy

IOp(5/45)

Numerical Derivative Coupling calculation(for testing) 0

No

1

Yes (Needs NonStd root and two cards in input stream): i3 the other vector which coupled with iVec; If negative reads the vector from rwf; If positive reads vector from input 4f20.8 f10.7: the displacement in geometry in internals in Angs. 10

Include the CSF contribution to the orbs for the DerCpl.

IOp(5/47)


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In L510, 1 to set up for CAS-MP2 or 2 to do spin-orbit calculation. 1

Prepare data for Mp2 (l906 obsolete)

2

Compute transition spin density and SO coupling

IOp(5/48)

Options to be passed to CalDFT: N

Control flag for CalDFT is N.

L510: Option for using reorthogonalization procedure in Lanczos 0

No

1

Yes

IOp(5/49)

Use of sparse storage and Conjugate Gradient optimization instead of N**2 memory and diagonalization. 0

Default (11, or 22 if sparse is set in ILSW).

1

Diagonalization

2

Conjugate gradient.

10

Square storage (only in Fock formation if CG).

20

Linear storage (only in Fock formation if diagonalization).

L510: Option for using lanczos in CPMCSCF calculations 0

No

1

Yes

2

Use lanczos except for the last iteration

IOp(5/50)

L510: Option for setting the maximum number of lanczos iterations in Direct CPMCSCF IOp(5/51)


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L510: Canonicalize MC-SCF orbitals by diagonalization of Core and Virt Fock operators. 0

Yes canonicalize. Speeds up convergence in CP-MCSCF

1

Do not Canonicalize (turn this on to maintain compatability with previous versions

of code.) IOp(5/52)

Amount of memory to allocate to stashing integrals. -1

None

0

Default, also none.

N

N words.

L510: configuration cutoff for mp2 0

.1

i

Float(1/i)

IOp(5/53)

PCM input and solvent type. N>0

Solvent type N, default parameters

N<0

Dielectric constant |N|/1000

IOp(5/55)

How many HOMOs and LUMOs to solve for after CG: 0 N

None. N of each.

L510: see below IOp(5/56)

A0 for Onsager SCRF. N

N/1000 Bohr.


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L510: See below IOp(5/57)

First iteration at which to level shift and do FON. 0

Default - 1 unless doing stable=opt, then start after instability searches.

L510: See below IOp(5/55-58)

L510: Switching on a State Averaged calculation graduately. Usefull for optimizations or trajectory calculations where only a part of the surface is (nearly) degenerate. The state averaging will be switched off (graduately) when the degenerate region is left. IOp(55) Number of steps over which the SA coefficients are brought from (0.0-1.0) to (0.5-0.5). (Or reversed, when the SA calculation graduately is switch off.) When IOp(55).lt.0, the calculation is started with coefficients (0.5-0.5), which is usefull when a trajectory is started at a degenerate region. In that case, the number of steps for switching on/off is -IOp(55). IOp(56) Threshhold for switching on. Energy difference smaller than IOp(56)*0.001 . Default is 0.050 IOp(57) Threshhold for switching off. Energy difference larger than IOp(57)*0.001 . Default is 0.075 IOp(58) When set, in link 1003 a normal frequency calculation is performed when the optimization is in a region of (0.0-1.0), instead of a State Averaged second derivatives calculation. 1: Normal computation when (0.0-1.0) (default) 2: Allways SA second derivatives THESE OPTIONS MUST BE SET IDENTICAL FOR OVERLAY 10! (only IOp(10/55) needs to be set in overlay 10) IOp(5/59)

IOp(59)

0

(Default) No action 1 Turn on new more flexible SA options: The old method switches

SA on when you reach certain energy gap, regardless of weather that continues to decrease after the switch point, this can cause jobs sensitive to SA to fail to converge The


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new method checks the gap each cycle and will decide to increase or decrease the SA based on that result, for a hypothetical example with nroot=2: cycle

old SA

new SA

Egap

45 0.2/0.8 0.2/0.8 limit 7 0.5/0.5 0.1/0.9 >limit 8 crash 0.0/0.1 >limit Note: trajectory option set in overlay 10: IOp(10/99)=n -- Threshold for a determining an adiabatic hop threshold=n*0.0001 (checks Offdiagonal element); only used with IOp(97)=11 IOp(5/60 - 62)

Override standard values of IRadAn, IRanWt, and IRanGd. IOp(5/63)

Whether to do FMM. 0

Use global default.

1

Turn off FMM here regardless.

IOp(5/64)

Over-ride default value of FMFlags 0 N

No. Yes, use N.

IOp(5/65)

Over-ride NFx parameter. 0 N

No. Yes, use N.

IOp(5/70)

Maximum Initial temperature for FON (non-PBC), or temperature for broadening (PBC and IOp(74)=[1-4]xx).


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-2

None

-1

Start at a high temperature (limited only by DIIS error).

0

Default (3000K = 10 milliHartrees for non-PBC, 6000K for PBC)

N

N degrees

IOp(5/71)

Number of steps to apply simulated annealing (L502): 0 N

Default -- 10 steps FON / 20 steps PFON N steps

IOp(5/73)

Options for ADMP: 0

Default (2)

1

Use Lowdin basis for CP orthonormal transform.

2

Use Cholesky basis for CP orthonormal transform.

IOp(5/74)

Type of k-point integration: 0

Default (911).

1

Use LT method (interpolation)

2

Occupy entire points (used together with broadening)

3

Full points for insulators, temperature broadening for metals.

9

Occupy lowest NE at each k point regardless of the energies

10

Improved LT with quadratic corrections

20

Original LT method

90

No concern for corrections


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100 Smearing Marzari method I 200 Smearing Marzari method II 300 First order Hermite-Gaussian of Paxton and Methfessel 400 Gaussian smearing 500 Classical Fermi-Dirac broadening 900 No broadening (this will be Gaussian broadening with small T) IOp(5/75-78)

Number of alpha electrons, alpha orbitals, beta electrons, and beta orbitals for fractional occupation. IOp(5/79)

Range around Fermi level where temperature distribution will be applied if broadening is turned on for PBC. 0

Default, a value will be chosen in ZInLT1.

IOp(5/80)

The maximum conjugate gradient step size -1

No maximum step size

0

Default maximum (.8)

MMNN

Step size of MM.NN

IOp(5/81)

Conjugate-Gradient Parameters MM

Maximum Number of CG cycles per SCF iteration. (defaults to 4 CG cycles).

NN00 cycles).

Maximum Number of purification cycles per CG iteration. (defaults to 3

00000

Don't use CG DIIS

10000

Use CG DIIS


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000000

Polak-Ribiere CG minimization

100000

Fletcher-Reeves CG minimization

0000000 Use diagonal preconditioning in Conjugate-Gradient. 1000000 No preconditioning. IOp(5/82)

C.G. Convergence criterion 0

Defaults to 10**(-7) N

10**(-N)

IOp(5/83)

Maximum SCF DIIS vectors 0 N

Default (20). Use SCF DIIS with N vectors

IOp(5/84)

Restart in L509, Restart using Fock matrix in L502. 0

No.

1

Yes.

IOp(5/85)

Over-riding of maximum cycles for XQC. -1

Default for first step (128).

0

No.

N

Limit is N cycles.

IOp(5/86)

Strategy options


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000000

Default (101100).

0

Default (1 except during Stable=Opt, then 4).

1

Just continue as usual if energy goes up.

2

Reduce DIIS space when energy rises from previous cycle.

3

Reduce DIIS space when energy goes above the lowest energy.

4

Reduce DIIS space whenever energy is above the lowest energy.

10

Turn on dynamic level shift from the beginning

20

Turn on dynamic level shift only after FON is over.

100 200

Keep level shift after energy rises. Turn off level shift after energy rises.

1000

Level shift to a maximum of the Goal.

2000

Level shift to a maximum of 2*Goal.

3000

Level shift as much as necessary for HOMO>LUMO.

4000

Level shift only if the HOMO-LUMO gap is zero.

5000

Level shift only if the HOMO-LUMO gap is zero or insignificant (>-0.1)

6000 Level shift only if the HOMO-LUMO gap is zero or insignificant (>-0.1), up to twice the goal N0000 No longer used. 100000 Turn off 3 and 4 point extrapolation if DIIS is on. 200000 Retain 3 and 4 point extrap. if DIIS is on. The energy is only checked after FON has been turned off. IOp(5/87)

Accuracy criterion in Fock matrix formation: 0

Default, set in FoFDir/FoFCou/CalDSu based on accuracy part of IOp(5). Typically 10^-10 for molecules and 10^-12 for periodic systems.


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N

10**-N.

IOp(5/88)

L510: controls the amount of printing; variable=kPrint 0

Print only summary information

1

Print the a(t) vector and probability for each csf

2

Print almost everything for debugging

3 Print everything for debugging warning! this is a lot of stuff and you will only be able to do a few cycles IOp(5/89)

Linearly dependent basis control for PBC; this and ZFormV should be moved to L302. IOp(5/90)

Whether to generate sparse guess here. 1

Yes, do preliminary AM1 calculation.

2 Yes, do preliminary AM1 calculation and compare with guess from previous step in geometry optimization. IOp(5/91)

Control option for chebyshev sparse control. IOp(5/92)

Whether to use FoFDir or FoFCou for exact exchange: 0 Default: normal processing based on FMM for non-PBC; separate Coulomb and NFx exchange for PBC). 1

FoFCou for Coulomb, separate FoFCou/NFx for exchange.

2

FoFCou for Coulomb, separate FoFDir for exchange.

L510: flag hopping controls starting and stoping options (x=0 or x=1)


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variable=iBack for first hop being up: xxxx0 Hopping down (forward) xxxx1 Hopping up (backward) variable=iStNow xxx0x xxx1x variable=iSpace xx0xx xx1xx

Use criteria to start timedep StartEnergy timedepgap imediately Use full space CI basis Use reduced space in projection of alpha

variable=iEnd number of cycles to carry on before stopping the timedep code after exiting the hopping region x0xxx Default stop 6 iterations later xNxxx Stop time dep on cycle N after exit (if IOp(92) is negative then stop immediately) variable=iFcTD to stop the time dependent code on cyle Z 0xxxx No effect Nxxxx Stop time dep on cycle N allowable values 1-9 IOp(5/93)

Number of initial iterations for which damping is allowed: 0 N

Default (10). N iterations.

L510: has different meaning depending on if you are using IOp(97)=22 or IOp(97=23) If IOp(97)=22, Value = xxxzyy, where: Zyy

Threshold for a hop down determined by probability of being on the upper state (=x*0.01) or the lower state (=(1-x)*0.01)

yy

Determines a variable Ulimt which lies between 01 and 99

Z Determines if this probability is halved after the first hop default Zyy=25, threshold =0.75 in ES (or 0.25 in GS) and if Zyy=125, threshold for a hop up (after a hop down) = 0.125 in GS


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xxx How long to wait before checking for a hop after going through a hop, variable=IWait; wait time is xxx*0.1 fempto seconds If IOp(97)=23, value=xxx, which determines what type of gradient calculation to do: xxN

Choose the basis variable=mBasis 0 (Default) same as 1 1 Use a(t) basis 2 Use mcscf basis orthogonal to a(1) and a(2) 3 Use currnet mcscf vectors to check the code must be used with mHTest=2

xNx

Do with diagonalisationof Ecc variable=mTDGrd: 0 (Default) same as 1 1 Only check Ecc if MCSCF energies are almost degenerate 2 Force check on Ecc by diagonalising it

N00

Testing options, variable=mHTest 0 (Default) no testing 1 Testing construction of ecc 2 Testing construction of the ecc or exx portion of hessian using the mcscf vector information 3 Calculate but do not use TD gradient IOp(5/94)

PCM/ONIOM calculation 0 1

Standard PCM calculation PCM/ONIOM calcn. on the real system

2

PCM/ONIOM calcn. on the model system

L510: Threshold for turning propagation method on and off yyy

The first three digits determine the energy gap for turning off

xxx

The last three digits determine the energy gap for turning on

Threshold =xxx*0.01 (checks energy gap); default xxx=4 ie deltaE<0.04 switch timdep on; default yyy=5 ie deltaE>0.05 switch timdep off only used with IOp(97)=22 and IOp(97)=23 IOp(5/95)

Option for using Davidson in RFO calculations


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0

Yes

1

No use Lanczos (not recommended)

IOp(5/96)

Over-ride IRadAn for CPHF-like step in L509, and for pass 0 grid in L502. 0 N

Use default, Use grid N.

RAS control in L510. The CAS active space is subdivided into three RAS active subspaces, Ras1, Ras2 and Ras3. In the reference space. Ras1 orbitals are doubly occupied. Ras3 orbitals are empty. We also need that to define maximum of subspace, holes in theand Ras1 (ie the number electrons can betheexcited out ofnumber the Ras1 the space maximum number of of electrons in the Ras3 space: zzyyxxww, where ww

Number of Ras1 orbitals

xx

Maximum number of holes in Ras1

yy

Number of Ras3 orbitals

zz

Maximum number of electrons in Ras3

IOp(5/97)

Whether to update precomputed grid data with timing information. 0

Default (Yes, if available).

1

Yes.

2

No. Hopping threshold during trajectories with L510.

10

Vector following or Root following hop alone (Needs option 80)

11 Make a hop based on the secular equation (adiabatic hop) this option also includes a hop decision based on the vector following method (diabatic hop) (Needs option 99 and 80) 21 Debugging Option: Propagation of the wavefunction is switched on, but the hop is determined by the diabatic or adiabatic criteria (whichever determines a hop first). Needs


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option 80 and option 99, for detailed control of the propagation conditions see options 92-96. 22 Propagation of the wavefunction, hop is based on the probability of being in a specific state (Needs also option 80) (detailed control is determined by options 92-96) 23 Propagation of the wavefunction but no hopping, the molecule continues in a mixed state (Needs option 71 and 80) IOp(5/98)

Whether to save eigenvalues and orbitals at all k-points. 0

Default (No).

1

Yes.

2

No.

IOp(5/99)

Grid for numerical k-integration in FT-LT method. 0

Default: 32,12,8 for 1,2,3d

IOp(5/100)

Tight convergence during CGDMS: 0

Default (No).

1

Yes.

2

No.

IOp(5/101)

SDif test on numerical accuracy of PBC diagonalization. 0

Default (10)

-1

No test

N>0 Abort of SDif is larger than N. IOp(5/102)


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Maximum number of configurations for CAS-MP2: 0

Default (1000). N

N.

L510 Notes These options must be set in multiple links: L1003 iop(97)

yes

yes

no

iop(55-59) yes

yes

no

iop(80)

no

yes

yes

L510

L118

These options must be set for the following links: IOp 55-58 80 97 98 99 l118

no

yes

no

no

no

l510

yes

no

yes

no

no

l1003

yes

yes

yes

yes

yes

Overlay 6

15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 70 71 72 73 74 75 76 77 78 79 80 81 82 IOp(6/15)

SPECIFICATION OF ADDITIONAL CENTERS. IF MORE THAN ONE OF THESE IS REQUESTED, THE LISTS ARE IN SEPARATE INPUT SECTIONS IN THE ORDER LISTED BELOW. 0 NO ADDITIONAL CENTERS. EVALUATE THE PROPERTIES ONLY AT EACH ATOMIC CENTER. 1 READ ADDITIONAL CENTERS. ONE CARD PER CENTER WITH THE X, Y AND Z COORDINATES IN ANGSTROMS (FREE FORMAT).


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2 READ IN COORDINATES AS FOR 1. STARTING AT EACH POINT, LOCATED THE NEAREST STATIONARY POINT IN THE ELECTRIC. POTENTIAL. 4

Read in a set of cards specifying a grid of points at which the electric potential will

be computed. Two forms of specifications are allowed: A. Evenly spaced rectangular grid. Three cards are required: KTape,XO,YO,ZO 0, it defaults to 51.

-- output unit and coordinates of one corner of grid. If KTape is

N1,X1,Y1,Z1

-- number of increments and vector.

N2,X2,Y2,Z2

-- number of increments and vector.

N1 records will be written to unit KTape, with N2 values in each record. B. An arbitrary list of points. Only one card is needed: N,NEFG,LTape,KTape The of N points in Angstroms will be read unit LTape in format (3F20.12). The coordinates potential (NEFG=3), potential and field (NEFG=2), or potential, field, and field gradient (NEFG=1) will be computed and written along with the coordinates to unit KTape in format (4F20.12). Thus if NEFG=3 for each point there will be 4 cards written per point, containing: X-coord,Y-coord,Z-coord,Potential X-field,Y-field,Z-field,XX-EFG YY-EFG,ZZ-EFG,XY-EFG,XZ-EFG YZ-EFG Note that either form of grid should be specified with respect to the standard orientation of the molecule. 8

Do potential-derived charges.


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16

Constrain the dipole in fitting charges.

32

Read in centers at which to evaluate the potential from the rwf.

128 Read grid; do not default cube. IOp(6/16)

Cutoffs in L602. 0 Use full accuracy in calculations at specific points, but use sleazy cutoffs in mapping a grid of points. 1

Do all points to full accuracy.

IOp(6/17)

DEBUGGING CONTROL (L602). 0

COMPUTE ALL CONTRIBUTIONS TO SELECTED PROPERTIES.

1

COMPUTE ONLY THE NUCLEAR CONTRIBUTION.

2

COMPUTE ONLY THE ELECTRONIC CONTRIBUTION.

-N

COMPUTE ONLY THE CONTRIBUTION OF SHELL N.

IOp(6/18)

Whether to update dipole rwf 0/1 yes/no. IOp(6/19)

Whether to rotate exact polarizability before comparing with approximate (which will be calculated in the standard orientation). This is like IOp(9) in L9999. 0

Default, same as 1.

1

Exact is still in standard orientation; use as-is.

2

Exact is already in z-matrix orientation, so rotate.

IOp(6/20)

How to do electrostatic-potential derived charges:


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0

Default (1).

-1

Read a list of points at which to fit, one per line.

1

Merz-Kollman point selection

2

CHELP point selection.

3

CHELPG point selection.

00

Default radii are those defined with the selected method.

10

Force Merz-Kollman radii.

20

Force CHELP (Francl) recommended radii.

30 Force CHELPG (Breneman) recommended radii. 100 Read in replacement radii for selected atom types as pairs (IAn,Rad) or (Symbol,Rad), terminated by a blank line. 200 Read in replacment radii for selected atoms as pairs (I,Rad), terminated by a blank line. 1000 Fit united atoms (heavy atoms only) rather than all atoms. 10000 Use only active atoms in the fit. IOp(6/21)

Operation of L603: 0


1

Read in density basis functions and compute populations.

2

Optimize density basis set.

IOp(6/22)

Selection of density matrix (currently only in L601, L602, L604): -1x

Read density matrices from .chk file.

+1x

Read density matrices from .chk file.


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-5

All available transition densities.

-4

Transition density between the states given by IOp(29) and IOp(30).

-3

Density for the excited state given by IOp(29).

-2

Use all available density matrices.

-1 Use the density matrix for the current method, or the HF density if the one for the current method is not available. N.ge.0 Use the density matrix for method N (see Link 1 for the numbering scheme). IOp(6/23)

Density values to evaluate over grid in L604: 0


1

Density values.

2

Density values and gradients.

3

Density values, gradients and divergence.

IOp(6/24)

Frozen core: -N

Freeze N orbitals.

0

Default (Yes).

1

Yes.

2

No.

IOp(6/25)

Whether to compute coulomb self-energy in L601: 0

No.

1

Yes, classically (including self terms - requires 2e integrals, O(N**4)).


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2 Yes, quantum mechanically (no self terms - requires 2e integrals, and only available for HF. O(N**5)). IOp(6/26)

Which density to use in L602 and L604: 0 Default (same as 1). 1

Total.

2

Alpha.

3

Beta.

4

Spin.

IOp(6/27)

Choice of population analysis: 0

Default (12).

1

Don't do Mulliken populations.

2

Do Mulliken populations.

10

Don't do bonding Mulliken Populations.

20

Do bonding Mulliken Populations.

100 Do Minimal population analysis. IOp(6/28)

Mark SCF density as current density. 0

No: save SCF density, but do not mark.

1

Yes: mark as well.

IOp(6/29)

Excited state to use if requested by IOp(22). IOp(6/30)


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2nd excited state for transition density: 0

Transition denstiy between state IOp(29) and g.s.

N

Transition denstiy between state IOp(29) and state N.

IOp(6/31)

Whether to determine natural orbitals from densities: 0

No.

1

Yes, using total density.

2

Yes, using alpha and beta separately for UHF.

3 4

Store only alpha NOs. Store only beta NOs.

5

Use spin density.

IOp(6/32)

CONTROL PARAMETERS FOR COVBON in L609 (NOT TO BE CHANGED UNDER MOST CIRCUMSTANCES): 10000*MItLoc+1000*ITlLoc+100*IDcInt+IPrLoc, where MItLoc

MItLoc*NOrb*(NOrb-1)/2 is the maximum number of iterations in localization of (spin)orbitals (1...9, default 6),

ITlLoc 10.**(-ITlLoc) is the convergence criterion for (spin)orbital localization (1...9, default 9), IDcInt

Localized (spin)orbitals with atomic occupancies less than 0.01*IDcInt are interpreted as lone pair MOs rather than bond MOs (1...99, default 10),

IPrLoc

0: Print the atomic occupancies of localized (spin)orbitals (default), 1: Do not print the atomic occupancies.

L605, L606: naming of RPAC interface file. 0

Make this a scratch file.


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1

Name this file 'rpac.11'

IOp(6/35)

WHAT TO DO: 0

Determine attractors, attractor interaction lines, ring points, and cage points.

1

Determine zero-flux surfaces (IDoZrF).

2

Compute charges of AIMs (IDoAtC).

4

Compute kinetic energies and multipole moments of AIMs (IDoPrp).

10 Compute energies of electrostatic interactions between AIMs (IDoPot). This precludes calculations of atomic property derivatives with respect to nuclear displacements. 100

Compute atomic overlap matrices (IDoAOM).

200

Compute other atomic matrix elements (IDoAMa).

400 Include zero-flux surface relaxation terms in all atomic matrix elements (IDoSRe) 1000

Compute derivatives of atomic properties with respect to electric field

(IDoSeP). Note that IDoSRe should be set to 1 in order to obtain correct results! Also note that analytical polarizabilities have to be available but force constants have to be absent! 2000 as

Compute derivatives of atomic properties with respect to nuclear displacements well (IDoNuD). Note that analytical force constants have to be available!

10000

Compute localized orbitals and bond orders (IDoLoc).

20000 Compute atomic orbitals in molecule (IDoAOs). 100000 If necessary, augment valence electron densities with relativistic core contributions, which is a default anyway (IHwAug=0). 200000 If necessary, augment valence electron densities with nonrelativistic core contributions (IHwAug=1).


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400000 Abort if pseudopotentials have been used (IHwAug=3). 1000000 Reduce accuracy so atomic charges can be computed more rapidly (IQuick). No other properties can be calculated. This option sets IPrNDe=5, IPrNAt=5, and IEpsIn=100. 2000000 Use numerical instead of analtyic integration. 3000000 Use numerical instead of analtyic integration and use reduced cutoffs. IOp(6/36)

CONTROL PARAMETERS FOR NEGLECT OF ORBITALS AND PRIMITIVES in L609: 10000*INoZer+100*IPrNDe+IPrNAt, where INoZer 0: Ignore (spin)orbitals with zero occupancies (default), 1: Do not ignore (spin)orbitals with zero occupancies, IPrNDe electron

Neglect primitive contributions below 10.**(-IPrNDe) in evaluations of density and its derivatives (0 99, default 7),

IPrNAt Neglect primitive contributions below 10.**(-IPrNAt) in integrations over atomic basins (099, default 7). IOp(6/37)

CONTROL PARAMETERS FOR ATINLI, RNGPNT, AND CAGPNT in L609 (NOT TO BE CHANGED UNDER MOST CIRCUMSTANCES): 1000000*MxBpIt+100000*SBpMax+1000*NGrd+LookUp, where MxBpIt 10),

Maximum number of iterations in trial path determination (1...99, default

SBpMax

Maximum value of the control sum (1...9, default 2),

NGrd

Length of Fourier expansion for the trial path (1...99, default 20),

LookUp

Number of grid points in critical point search (1...999, default 100).

IOp(6/38)


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CONTROL PARAMETERS FOR ZRFLUX AND OIGAPI in L609 (NOT TO BE CHANGED UNDER MOST CIRCUMSTANCES): 100000*INStRK+10000*IHowFa+1000*IGueDi+100*IPraIn+10*IRScal+IRtFSe INStRK 10*INStRK is the gradient paths (1...9, default 2),number of steps in the Runge-Kutta integrations along IHowFa IHowFa is the maximum distance in the Runge-Kutta integrations along gradient paths (1...9, default 5), IGueDi 10.**(-IGueDi) is the initial displacement from the critical point in the Runge-Kutta integrations (1...9, default 6), IPraIn

10.*IPraIn is the cut-off for zero-flux surfaces (1...9, default 2),

IRScal IRScal is the scaling factor in the nonlinear transformation used in the intersection search (1...9, default 2), IRtFSe 2).

10.*IRtFSe is the safety factor used in the intersection search (1...9, default

IOp(6/39)

More CONTROL PARAMETERS FOR ZRFLUX AND OIGAPI in L609 (NOT TO BE CHANGED UNDER MOST CIRCUMSTANCES): 1000000*IToler+100000*INInGr+10000*INInCh+1000*IEpsSf+10*IEpsIn+INTrig IToler

10.**(-5-IToler) is the tolerance for the intersection search (1...9, default 5),

INInGr 10*INInGr is the initial number of grid points in theta and phi in the adaptive integration subroutine (1...9, default 2), INInCh 5+INInCh is the initial number of sampling points in the intersection search (1...9, default 2), IEpsSf IEpsSf is the safety factor used for patches with surface faults in the adaptive integration subroutine (1...9, default 6), IEpsIn

0.0001*IEpsIn is the target for integration error (1...99, default 2),


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INTrig 10*INTrig is the number of sine and cosine functions in the trial function for surface sheets (1...9, default 2). IOp(6/40)

Control of link 607. 0 Default NBO analysis - don't read input. 1

Read input data to control NBO analysis.

2 Delete selected elements of NBO Fock matrix and form a new density, whose energy can then be computed by one of the SCF links. This link must have been invoked with IOp(40) = 0 or 1 prior to invoking it with IOp(40)=2. 3

Read the deletion energy produced by a previous run with IOp(40)=2 and print it.

IOp(6/41)

Number of layers in esp charge fit. 0

Default (4).

N

N layers, must be >=4.

IOp(6/42)

Density of points per unit area in esp fit. 0

Default (1).

N

points per unit area.

IOp(6/43)

Increment between layers in MK charge fit. 0

Default (0.4/Sqrt(#layers)) N

0.01*N.

IOp(6/44)

Type of calculation in L604:


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0

Default, same as 2.

1

Compute the molar volume

2

Evaluate the density over a cube of points

3

Evaluate MO's over a cube of points

10

Skip header information in cube file.

IOp(6/45)

Number of points per bohr**3 for Monte-Carlo calaulation of molar volume -1

Read from input

0 N

Default (20) N points - for tight accuracy, 50 is recommended.

IOp(6/46)

Threshold for molecular volume integration. 0

Default - 10**-3

-1

Read from input.

N

N*10**-4.

IOp(6/47)

Scale factor to apply to van der Waals radii for the box size during volume integration: 0

Default.

N

N*0.01 - for debugging.

IOp(6/48)

Use of cutoffs 0 Default (10**-6 accuracy for cubes, 1 digit better than desired acuracy for volumes).

N

10**-N


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IOp(6/49)

Approximate number of points per side in cube in l602/l604: 0

Default (80)

N

N points

-1

Read from cards.

-2

Coarse grid, 3 points/Bohr.

-3

Medium grid, 6 points/Bohr.

-4

Fine grid, 12 points/Bohr.

-N>4 Grid using 1000 / N points/Bohr. IOp(6/51)

Whether to apply Extended Koopman's Theorem (EKT): 0

Default (No).

N

Yes, on non-SCF densities, up to N IPs and EAs.

-1

Yes, on non-SCF densities, all possible IPs and EAs.

-2

No.

IOp(6/52)

Number of radial integration points in L609: 0

Default (100). N

N.

IOp(6/53)

Distribution of radial points in L609: 0 N

Default (cubic) Polynomial of order N.


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IOp(6/54)

Maximum number of domains. 0

Default (100000). N

N.

IOp(6/55)

Number of inner angular points in numerical integration in L609: -1

0 (no inner sphere)

0

302

N

N point Lebedev grid (see AngQad).

IOp(6/56)

Whether to read in density matrix from input stream in L608. 0

No.

1

Yes.

IOp(6/57)

Whether to generate data over a grid using the total SCF density: 0

No.

1

Yes, read in name for output file.

2

Yes, also read in name for input file with a different grid and compare.

3

Output in the form of data statements.

IOp(6/58)

Grid to use in generating tables of density and potential. Must be an unpruned grid. 0

Default (99001).

IOp(6/59)


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Approximations to Exc -1

Test superposition of atomic densities using L608:

0

Do correct energies.

1

Do correct energies and 0th order approximation

2

Do correct energies and 0th-1st order approximations

3

Do correct energies and 0th-2nd order approximations

IOp(6/60-62)


Suppress number of electrons test in XC quadrature in L608 (for debugging with small grids): 0

Default (do test).

1

Suppress test.

2

Do test as usual.

IOp(6/64)

Natural Chemical Shielding Analysis: 0

No.

1

Yes, of isotropic value.

2

Yes, of diagonal tensor elements and isotropic value.

3

Yes, of all tensor components.

IOp(6/65)

Threshold for printing of NCS contributions. -1

Zero.

0

Default (1 pmm).


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N

N/1000 ppm

IOp(6/70)

Control of L610. IOp(6/71)

XC functional in L610. IOp(6/72)

Whether to read isotopes for hyperfine interractions and do hyperfine terms in L602: 0

Default (1).

1

Yes, if open-shell, NMR data is available, and other terms are being computed

2

No.

3

Yes, regardless of other terms.

4

Yes, reading isotopes

IOp(6/73)

Whether to save orbitals from NBO: 0

Default (No).

1

Save NBOs in place of regular MOs.

2

Save NLMOs in place of regular MOs.

3

Save NLMO occupieds and NBO virtuals.

10

Suppress re-orthogonalization.

IOp(6/74)

Whether to use Gaussian connectivity in choosing Lewis structure for NBO. 0

Default (use if present and choose is selected in NBO input).

1

Use.


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2

Don't use.

IOp(6/75)

model for CM2 charges. IOp(6/76)

Threshold for linear dependence in L607. 0

Default (1.D-6). N

10**(-N).

IOp(6/77)

Restraint in charge fitting in L602: 0

None.

-1

2.d-4

N

N * 10^-5.

IOp(6/78)

Use MOs instead of density in AtmTab. 0

Default (2).

1

Use density.

2

Use MOs.

IOp(6/79)

Whether to calculate Hirshfeld charges. 0

Default (No).

1

Yes.

2

No.

IOp(6/80)


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Whether to calculate Lowdin charges and Mayer bond orders. 0

Default (No).

1

Yes.

2

No.

IOp(6/81)

Print kinetic energy of orbitals? 0

Default (yes, if doing other orbital results).

1

Yes, for the top 5 occupieds and lowest 5 virtuals.

2 3

No. Yes, for all orbitals.

IOp(6/82)

Tensors for hyperfine spectra. 0

Default, compute if there are 100 or fewer atoms

1 Compute QEq tensors and for open-shell systems compute isotropic and anisotropic splitting tensors. 2

Do not compute tensors.

Overlay 7 6 7 8 9 10 11 12 13 14 15 16 18 25 29 30 31 32 40 41 42 43 44 45 52 53 64 65 70 71 72 74 75 76 77 87 IOp(7/6)

operation of link 705 (NYI). 0

Default (12).

1

Do not the ecp contribution to the SCF forces.

2

Form the ecp contribution to the SCF forces.


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10

Do not form 1e derivative matrices.

20

Increment the 1e derivative matrices with ecp terms.

IOp(7/7)

USE OF INTERNAL COORDINATES. 0

YES

1

NO

2 Yes, but neglect first derivatives in conversion of second derivatives to internal coordinates. IOp(7/8)

Harmonic frequency calculation: 0

No.

1

Yes, with most common isotopes.

2

Yes, with read-in isotopes.

3

No.

10

Print higher precision normal modes.

20

Print normal mode displacements in redunant internals.

30

Print both HP modes and internal displacements.

Nxx

Default scale factor is #N (1=HF, 1/1.12, 2=CBS4=0.91671, 3=CBSQ=0.91844)

Mxxx

If M=1, only harmonic thermochemistry. If M=2, do hindered rotor analysis. If M=3, Read hindered rotor parameters from input.

IOp(7/9)

Whether to rotate derivatives back to the z-matrix orientation. 0/1 yes/no. IOp(7/10)


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First/second derivative control. 0

do only first derivatives.

1

do only second derivatives.

2

do both.

IOp(7/11)

control of integral derivative algorithm: 0

Default

use IsAlg to decide.

2

Scalar Rys SPDF.

3 4

Berny SP, Scalar Rys DF. Old vector Rys SPDF.

5

Berny SP, old vector Rys DF.

6

FoFDir: Rys spdf.

7

Berny SP, FoFDir Rys df.

8

FoFDir: HGP sp, Rys df.

9

Berny SP, FoFDir Rys df (same as 7).

10

FoFDir: HGP spd, Rys f.

11

Berny SP, FoFDir HGP d Rys f.

12

FoFDir: HGP spdf.

13

Berny SP, FoFDir HGP df.

14

FoFDir: PRISM spdf.

15

FoFDir: Berny SP, PRISM df.

IOp(7/12)

Selection of density matrix.


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0

Usual SCF density.

N Use generalized density number N for both the one-electron integral derivatives and the corresponding 2PDM terms. IOp(7/13)

Contraction with two-particle density matrices: 0


1

Use HF 2PDM.

2

Use external 2PDM.

3 4

Use both HF and external 2PDM. Generate 2PDM from CIS square 1PDM (for debugging)

5

Generate 2PDM from CIS square 1PDM and use HF/Z 2PDM as well.

6 Contract with external 2PDM derivatives. The types of derivatives are given by IOp(15). 7 Form derivative 2PDM from CIS and HF derivative density matrices. The types of derivatives are given by IOp(15) 10

Leave the external 2PDM on the disk instead of deleting it.

0-5 imply use of the generalized density in L701, while 6-7 imply use of the generalized density derivatives in L701. IOp(7/14)

State for CIS gradients. Defaults to 1. IOp(7/15)

The nature of the perturbation(s). 0

Default (1st order nuclear and electric field).

IJK Nuclear Kth order. Electric field Jth order. Magnetic Field Ith order.


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1000 Generate simulated density derivatives. Only 1, 10, and 11 are valid in overlay 7. IOp(7/16)

Number of translations and rotations to remove during redundant coordinate transformations: -2

0.

-1

Normal (6 or 5 for linear molecules).

0

Default, same as -1.

N

N.

IOp(7/18)

Derivative accuracy option: 0

Compute to 10**(-8) accuracy.

1

DO AS ACCURATELY AS POSSIBLE in L702.

2

USE THE ORIGINAL 'BERNY' VALUES in L702.

10

DO AS ACCURATELY AS POSSIBLE in L703.

20

Use sleazier cutoffs in L703.

100 DO AS ACCURATELY AS POSSIBLE in L708. 200 Use sleazier cutoffs in L708. IOp(7/25)

Type of derivatives available. 0

First.

1

Second.

2

Third.

10

Read derivatives from checkpoint file (in Z-matrix orientation).


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IOp(7/28)

SKIP OPTION TO DEFER INTEGRAL EVALUATION TO L703. 0

COMPUTE AS NORMAL.

2

DO ALL GRADIENT INTEGRALS IN L703

IOp(7/29)

MODE OF USE OF L716. 0

Normal, same as 2.

1

Normal + Generate estimated initial force constants.

2

Normal

6

NUCLEAR REPULSION ONLY (USEFUL FOR TESTING).

00

Default method for initial force constants

IOp(7/30)

USE OF SYMMETRY IN OVERLAY 7: 0

USE (SUBJECT TO AVAILABILITY).

1

DON'T USE.

IOp(7/31)

Handling of forces contributions. 0

Just use the forces in IRWFX.

1 Compute HF forces from D2E file and increment both FX and FXYZ (non-O11 PSCF grad and HF freq). 00 Use FX in conversion of force constants to internal coordinates. (HF freq, PSCF freq=numer). 10 Use FXYZ in conversion of forces constants to internal coordinates (PSCF opt with HF 2nd deriv). IOp(7/32)


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PUNCH OPTION. 0

None.

1

Punch energy in format D24.16, forces and lower triangular force constants in

format 6F12.8. 2 Punch nuclear coordinate derivatives. Forces are punched in 3D20.12 format, one card per atom. Force constants and third derivatives are punched in 4E20.12 format in compressed form. 3

Punch energy, coordinates, and derivatives in cartesians and redundant internals.

4 Punch energy, coordinates, and derivatives in redundant internals only in compressed form. 5 Punch energy, first and second derivatives in both cartesian and internal coordinates. 1x

Do punch only if second derivatives are available.

IOp(7/40)

Neglect of integrals (only option 1 works in Overlay 7): 0

Keep all integrals.

1

Neglect four center integrals.

2

Neglect three center two-electron integrals as well.

3

Neglect 2e integrals with diatomic differential overlap.

10

Neglect three center one-electron integrals.

20


30


IOp(7/41)

NDDO flag. 0

Evaluate integrals correctly.


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1

Apply NDDO approximation.

IOp(7/42)

1PDM: 0 N

Use SCF total density. Use generalized density N.

IOp(7/43)

2nd order simultaneous optimization flag. 0

.false.

1

.true. (other 2nd derivative options must also be set appropriately)

2

.true. (debugging option: compute fifth order WG and GG terms in L715)

IOp(7/44)

Handling of an applied electric field. -1

Do not add electric field terms to forces.

0

Update forces for a uniform electric field.

1

Update forces for the self-consistent reaction field (SCRF) method

2 Update forces for a uniform electric field, with forces done the usual way for CIS or MP2 2nd derivatives. IOp(7/45)

Controlling the projection of the reaction path. 0

Do not project. The point is a stationary point.

1

Project the reaction path and compute 3N-7 frequencies.

2

Project using the Newton-Raphson step.

3

Project using forces if the RMS force is larger than 1.d-6.

IOp(7/52)


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Whether ECP integrals should be done in L701 as usual. 0

Yes.

1

No.

IOp(7/53)

Convert forces over shells to field-dependent dipole and forces over atoms (for debugging): 0

No.

1

Yes.

10

Compute optimimum lambdas.

IOp(60-62)

IOp(60-62)

Over-ride standard values of IRadAn, IRanWt, and IRanGd.

IOp(63)


Use global default.

1


IOp(7/64)

Type of simulated spectrum in output. 0

Default (1).

1

Lines

2

Lorenzians

3

Both

IOp(7/65)

Harmonic constraints with respect to initial structure during geometry optimization. -1

No.


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0

Default (Yes, if ref structure is present and has non-zero force constants).

1

Yes.

IOp(7/70)

Do vibro-rotational analysis: 0

Default (No).

1

Yes.

2

No.

IOp(7/71)

Do vibrational 2nd order perturbation: 0

No

1 Yes. Currently lots of hacks to determine where we are in the process instead of different values of this option. IOp(7/72)

Read additional parameters for anharmonic computations 0

No

1

Yes

IOp(7/74)

Non-equilibrium PCM gradients: 0

No.

1

Yes.

IOp(7/75)

Threshold for printing redundant internal contributions to normal mode displacements: 0

Default (10%) N

10**-N


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-1

Zero (all printed).

The threshold is automatically lowered for each mode until 90% of the absolute displacements are included. IOp(7/76)

Over-ride use of FoFCou in L703: 0

Normal processing.

1

Force FoFCou.

2

Prohibit FoFCou.

IOp(7/77)

Debuging options for DBFs: 0

Normal processing.

1

Omit subtraction and do P(Fit)*Jx*P.

2

Copy fit density over real density and do P(Fit)*Jx*P(Fit).

3

Turn off 1c logic for 1c DBF case.

4

Clear real density and do -1/2 P(Fit)*Jx*P(Fit).

IOp(7/87)

Accuracy in FoFDir/FoFCou/CalDSu: 0

Default, 10^-10 for molecules, 10^-12 for PBC. N

10**(-N).

Overlay 8 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 27 28 29 30 31 32 35 36 38 39 40 41 42 43 44 45 46 47 IOp(8/5)

Whether to pseudocanonicalize ROHF orbitals.


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-1 0

Yes. No.

IOp(8/6)

Bucket selection. 0

BUCKETS FOR MP2: (IA/JB).

1

BUCKETS FOR STABILITY: (IA/JB),(IJ/AB).

2

BUCKETS FOR CID OR MP3: (IJ/AB),(IA/JB),(IJ/KL).

3 BUCKETS FOR SEMI-DIRECT MP4DQ, CISD, QCISD, BD: (IJ/AB),(IA/JB), (IK/KL),(IJ/KA). 4

CISD or MP4SDQ or MP4SDTQ, BUT INCLUDES (IA/BC).

5

THE COMPLETE SET OF TRANSFORMED INTEGRALS.

6

Full transformation if this is consistent with MaxDisk, otherwise same as 3.

7

Full transformation if this is consistent with MaxDisk, otherwise same as 4.

IOp(8/7)

SCF convergence test. 0

Test that SCF has convergd.

1

Do not test SCF convergence (mainly used for testing).

IOp(8/8)

Whether to delete MO integrals in L811. 0

Default (No).

1

Yes.

2

No.

IOp(8/9)

Debug control (L802):


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0

Operate normally.

-N

Force N orbitals per pass.

Direct Transformation Control (L804, L811): 0

Operate normally.

1

Generate and test RInt3 array (L804).

2

Accumulate MP2 force constant terms in direct fashion

3

Write the MO basis first derivative ERI's to disk

10

Force fully in-Core algorithm (L804 only).

20 30

Force transformed integrals in Core algorithm. Force semi-direct transformation.

100

Force output bucket in Core antisymmetrization.

200

Force sorting for output bucks.

1000 Force semi-direct mode 1. 2000 Force semi-direct mode 2. 3000 Force semi-direct mode 3 if IOp(6)=3. 4000 Force semi-direct mode 4 if IOp(6)=3. 00000 Default (10000) 10000 Do not symmetry compress transformed integrals. 20000 Do symmetry compress transformed integrals (buckets) (This will cause windowed MOs, rep2,... reordered in the order of representations like occ-rep1,occ-rep2,... virt-rep1,virtEigenvalues and symmetry assignment vectors will be put in correspondence with vectors.) 30000 Symmetry compress transformed integrals only if RHF. (Upper triangle of symmetry compressed integrals for IOp(6)=5 or 4 only!)


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100000 Reorder MOs, eigenvalues and symmetry assignment vectors according to ther representations IOp(8/10)

Window is selected as follows: -N Use the top N occupieds and lowest N virtuals. 0

Default, same as 4.

N

1 <= N <= 89 selects frozen-core type N:

1

The largest noble gas core is frozen.

2

G2 frozen-core: the largest noble gas core and main group d orbitals are frozen,

except that the outer sp electrons of 3rd row and later alkalai and alkalai earth elements are retained. 3

The next to the largest noble gas core is frozen.

4 The largest noble gas core and main group d's are frozen. For basis sets with double-zeta cores, core virtuals are also frozen. 90

Use all MOs.

91 The window is specified by IOp(37-38). If IOp(37) is 0, a card is read in indicating the start and the end. A negative value for the end deletes the top virtuals. 92

The window is recovered from rwf 569.

93

The window is recovered from file 569 on the checkpoint file.

94

Read a list of orbitals to freeze.

000

Default (200).

10x

Use orbital energies to choose core orbitals.

20x

Use overlap with atomic core orbitals from Harris to choose core orbitals.

30x

Use overlap with atomic core orbitals from Core Ham to choose core orbitals.

IOp(8/11)


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MO coefficient, orbital energy, and number of electrons test. 0

Default, same as 2

1

Just print a warning message.

2 Kill the job if any mo coefficients are greater than 1000.0 or the smallest difference between occupied and virtual orbital energies is less than 0.001. Also, kill a frozen-core job if there there is significant core-valence mixing in the canonical orbitals 00


10

Suppress such a test (CPHF may still be done for such a case).

20 Kill the job if there is no correlation energy; e.g., if there is only 1 electron or 1 virtual spin-orbital. IOp(8/12)

Calculation of frozen-Core contributions. 0

No.

1 Calculate 2 J - K over deleted orbitals and add to Core-Hamiltonian. This is done when IOpCl=0 or when IOpCl=1 and the calculation is rohf or gvb. IOp(8/13)

Control of output. Used to select output mode. 0

Output to Gaussian system buckets.

1

Output transformed integrals for DRT-CI calculation.

IOp(8/14)

Control of drt input. 0

Take necessary input from Gaussian data structures.

1

Read 'old-style' drt input cards.

IOp(8/15)


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Control of DRT output. 0

Write DRT output to RW-files.

1

Write DRT output to Fortran unit 'drttap'.

2

Do both.

IOp(8/16)

Maximum number of orbitals per pass in L811. (only if integral derivative file is being written) Excitation level for SDGUGA-CI. 0 N

Default excitation level = 2. Excitation level = N.

IOp(8/17)

Specification of integral block size for GUGA CI programs. 0

Default let program decide.

N

Integral Block Size = N.

IOp(8/18)

Which type of derivative transformation to do in L811: 0

Default, same as 3.

1

Non-canonical, Uij,x = -1/2 Sij,x.

2 Canonical, Uij,x = (Fij,x - EjSij,x) / (Ei-Ej) Note that this blows up for degenerate orbitals and is intended primarily for debugging. 3

Non-canonical, Uij,x = -1/2 Sij,x, except canonical in frozen-active blocks.

4

Non-canonical, Uij,x = -Sij,x Uji,x = 0.

5

Canonical occupieds, Uab,x = -Sab,x/2

6

Canonical virtuals, Uij,x = -Sij,x/2


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IOp(8/19)

The nature of the perturbation(s) in L811: 0


IJK Nuclear Kth order. Electric field Jth order. Magnetic Field Ith order. IOp(8/20)

Which terms to include in L811: 0


1

MO derivative times integral term.

10

MO times integral derivative term.

IOp(8/22)

These options control the in-Core post-SCF link, L805. Look there for more information. IOp(8/27)

Maximum amount of disk to use in L804 and L811: 0 N

Unlimited. N words.

IOp(8/28)

Hack number of occupieds for full ci using links 921 or 922: -1 Transform all orbitals (after freezing Core) as occupieds (i.e., set NOA=NOB=NROrb in transformation). 0

No.

N Transform N orbitals (after frozen Core) as occupieds (i.e., set NOA=NOB=N for purposes of transformation). IOp(8/29)


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Maximum number of perturbations per batch in L811: (only applies if integral deriv file is written) -3

Do not use batching logic.

-2 Do asintegrals. many in a batch as can be overlapped with sorting space for half transformed -1

Do one batch, but use multi-batch logic.

0


1

Do a single atom at a time (minimum disk usage).

N

N triplets.

Requested usage. This will overridden determine the times AOapplies integrals andintegral derivativesdisk are evaluated unless by number IOp(31).ofThis only if the derivatives are not stored. -3

Use as much as desired, independant of MAXDISK.

-2 Use an amount which is similar to the maximum disk usage in other parts of the MP2 frequency code. -1 Use as much as needed for maximum efficiency, subject to the limit imposed by MAXDISK (IOp(27)). 0

Default (-1)

N N evaluations and hence N coarse tiled batches (1...6 are the currently implemented options) IOp(8/30)

Type of window. 0

Default. Set up /Orb/ as indicated by IOp(10).

1

Test window. Set up for full but zero Core MOs.

-1 Set up /Orb/ for a full window but then blank the wavefunction coefficients in L804. IOp(8/31)


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PERFORM PRIMITIVE POST-SCF OPERATIONS (NOT CURRENTLY FUNCTIONAL). 0

NO

1

YES

IOp(8/32)

Whether to do CI in the interacting space only. 0

Default (all spin-eigenfunctions).

1

All.

2

Interacting only.

IOp(8/35)

Output format for closed-shell and debugging control: (only for when integral derivative file is written) 0 Default (consistent with integrals for open-shell, i<=jab alpha-beta only for closedshell). 1 Store only the unique AB integral derivatives (gO2V2/4, order g i,=j a<=b) for closed-shell 2 AA and AB consistent with integrals. 10

Do extra debugging computations.

Explicit control of the fine tile batch size (largely a debugging option, only for no-Ix routines). 0

Let the program choose (make it as large as possible)

N

maximum fine tile batch size, up to 9.

IOp(8/36)

Whether to update force constants with the MP2 product of MP2 integral derivatives term (only applies if integral derivative file is not written). 0

Default (Yes).

1

Yes.


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2

No.

00 Default on whether to make Poo and Pvv for MP2. (Yes if Ix is not stored, no otherwise). 10 20

Yes. No.

IOp(8/38)

Integers specifying the window to use. IOp(8/39)

Localized orbital method adopted in SAC/SAC-CI. 0

Default. No localization.

1

Boys method.

2

Population method.

3

Boys + population method.

IOp(8/40)

Handling of ROHF window: 0

Default (2).

1 Use ROMP2 approach, forming pseudo-canonical alpha and beta orbitals and doing UHF transformation. 2

Treat as RHF, transforming only alpha orbitals.

IOp(8/41)

Transformation of spin-orbitals (alpha only) within occupied and unoccupied orbital subspaces by minimum orbital-deformation (MOD) method. 0

Default. No.

1

No, but save MOs.

2

Yes. Take reference MOs from disk if available.


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3

No for the 1st geometry of opt, yes otherwise.

00

Rotate MOs to compute the displaced overlap.

10

Force to rotate MOs. If C1, use unity as rotation.

20

Force not to rotate MOs.

IOp(8/42)

Whether to reorder MOs during potential surface exploration. 0

No

1

Yes.

2 00

Yes. (for SAC-CI single point calculation) Use orbital energies in ordering

10

Don't use orbital energies in ordering

000

Use second moments in ordering

100

Don't use second moments in ordering

0000 Use dipole moments in ordering 1000 Don't use dipole moments in ordering IOp(8/43)

Number of Laplace points to use. N

Use N points for MP2.

-N

Use N points and set up for band gap correction.

IOp(8/44)

K-point specification for MP2 band correction. 0 N

Use the k-point for which the hoco is highest and luco is lowest. K-point at which to apply correction.


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IOp(8/45)

Type of quasiparticle job: 0

Band gap.

-1

Ionization potential.

1

Electron affinity.

-N N-th occupied band at the k-point for which the hoco is highest (by default) or at k point specified by IOp(44) N N-th virtual band at the k-point for which the luco is lowest (by default) or at k point specified by IOp(44) IOp(8/46)

Indicates special case of non-HF calculation. 0

Default - MOs are canonical HF orbitals.

1 Input orbitals are not canonical HF and pseudocanonical orbitals must be generated here for the post-SCF. IOp(8/47)

Whether 804/811 should generate results compressed over active atoms: 0

Default (2).

1

Active atoms.

2

Full list.

3 Full list, but blank contributions from inactive atoms. No difference from 2 for overlay 8.

Overlay 9 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 25 26 27 28 30 31 36 37 38 40 41 42 43 44 45 46 47 48 49 60 61 62 70 71 72 73 74 75 81 82 83 84 85 86 IOp(9/5)


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METHOD 0 CIDS. CONFIGURATION INTERACTION WITH ALL SINGLE AND DOUBLE SUBSTITUTIONS. 1 2

CID. CI WITH ALL DOUBLE SUBSTITUTIONS. MP3. THIRD ORDER PERTURBATION THEORY.

3 MP4(DQ). FOURTH ORDER PERTURBATION THEORY IN THE SPACE DOUBLE AND QUADRUPLE SUBSTITUTIONS. 4

MP4(SDQ). FOURTH ORDER PERTURBATION THEORY IN THE SPACE SINGLE, DOUBLE AND QUADRUPLE SUBSTITUTIONS.

5 MP4(SDTQ). FULL FOURTH THEORY IN THE SPACE OF SINGLE, DOUBLE,ORDER TRIPLEPERTURBATION AND QUADRUPLE SUBSTITUTIONS. 6

CCD. COUPLED CLUSTER THEORY WITH DOUBLE SUBSTITUTIONS.

7 CCSD. COUPLED CLUSTER THEORY WITH SINGLE AND DOUBLE SUBSTITUTIONS. 8

QCISD.

9

BD.

IOp(9/6)

L913: CRITERIA FOR TERMINATION OF THE ITERATION 0

DEFAULT CONVERGENCE CRITERION AND MAXCYCLE

-1

READ IN MAXCYCLES AND CONVERGENCE CRITERION (I2,D18.13)

N

Max N cycles.

L914: MAXIMUM NUMBER OF EXPANSION VECTORS IN DAVIDSON SCHEME 0 N

200 VECTORS N VECTORS


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**** NOTE: WHEN EXPANSION VECTORS EXCEED THE MAXIMUM, DAVIDSON RESTARTS WITH CURRENT EIGENVECTORS AS INITIAL GUESSES. IOp(9/7)

UPDATE THE ENERGY IN COMMON/GEN/ 0

YES, WITH THE CORRELATION ENERGY, ECID IN CID, ECISD IN CISD EUMP3 IN MP3, AND EUMP4 IN MP4 CALCULATIONS

1

YES, WITH EUMP3.

2

YES, WITH EMP4(SDQ) OR EMP4(DQ) IF SINGLES ARE NOT AVAILABLE.

7

NO

IOp(9/8)

L902: Constraint on output wavefunction for stability calculations (see link 902). Number of roots in 907 and 919, default 1 in 907 and 10 in 919. Term and method selection for debugging in 906. L913: Whether to use fast routines: 000 Default (no Slava, fast and R where possible). 1

Original code (DD1,2,3, UMP41,2,3,4) for first iteration

2

Use DD[1-3]R and UMP4xR (closed-shell) on 1st iteration

10

Original code for 2nd and later iterations.

20

Use DD[1-3]R and UMP4xR (closed-shell).

30

Use DD1, UMp41U, UMP42, UMP43, DD4UQ

40

Use DD1R, UMP41R, UMP42, UMP43, DD4RQ (closed-shell).

000

Default, same as 1.

100

Original routines.

200

Slava routines.


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The defaults are 22 for RCI, 11 for UCI, 42 for RQCI, and 31 for UQCI. L914: State of interest: 0

WE ARE NOT DOING GRADIENTS, FP OR CIS-MP2

N

WE ARE INTERESTED IN THE NTH EXCITED STATE

IOp(9/9)

Convergence criterion (on energy for L913, wavefunction for L914). 0

Default: L913 single point: 10**-7 energy, 10**-5 wfn. L913 gradient: 10**-8 energy, 10**-6 wfn. L914 single point:n: 10**-4 wfn. L914 gradient: N 10**-N.

10**-6 wfn.

IOp(9/10)

Test flag in link 902 Whether to do "fake" frozen-core (i.e., with a full transformation). Only active in L914. 0

No; follow /Orb/.

1

For AO usage (NYI here).

2

Yes, note number of frozen core and virtual and reset /Orb/ for full.

3

Yes, and store full /Orb/ back on disk.

IOp(9/11)

Flags for Green's function calculations: 0

Normal use of MO integrals.

1

Force direct computation of contributions.

2

Force direct computation of contributions.

00

Normal production of intermediates (in-core if possible).


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10

Force use of sort for intermediates.

100 Read window of MOs to refine in the same format as 801, but with two ranges on the same line for open-shell. 1000 Force N**3 algorithm in GFSCMA. 10000 Read EMin, EMax, and pole strength warning level on one line. Link 909 only. Test flag in l902. Spin projection control in L913: 0

Default (1)

1

Do basic projection.

2

Include triples?

IOp(9/12)

Test flag in l902. IOp(9/13)

Symmetry constraint of output wavefunction from stable=opt: 0/1 yes/no. IOp(9/14)

Non-iterative corrections: ICNonI 0

No.

1

Fourth-order triples (NYI).

2

Fourth and fifth order singles and triples - QCISD(T), BD(T).

3

Same as 2, but save the amplitudes.

4

Same as 2, but do E4T as well.

IOp(9/15)


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Type of derivative information generated: 0

None.

1

Do Lagrangian in L906; Do gradient in L913, included Z-amplitudes if necessary.

2

Do AO derivatives and Lagrangian in L906.

IOp(9/16)

L906: Control of (Semi-) Direct MP2: -N Do a maximum of (-N-6) occupieds per pass, using the fully out of core allgorithm. -6

Force the fully in-core algorithm.

-5 Try to minimize integral evaluations as for -3, but also force use of the fully outof-core algorithm in Tran4D. -4 Force a single integral evaluation as for -2, but also force use of the fully out-ofcore algorithm in Tran4D. -3 Try to minimize integral evaluations, using fully direct methods if possible, otherwise spilling to disk. -2

Force a single integral evaluation (two for UMP2) using disk-based algorithm.

-1 Force in-memory algorithm (fully direct MP2, requires 2OVN words of memory for E2, 2N**3 words for derivatives). 0

Default (same as -3)

M

Use disk storage for partially transformed integrals handling M occupieds at once.

L913, L914: Control of in-core integrals for W(Tilda): -6 -3

Force in-core storage. suppress in-core storage.

0

default: in-core if possible.

1

Use AO integral algorithm (L914 only).


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IOp(9/17)

Auto-adjustment of tau in L918. Functional to use in L914. IOp(9/18)

ITERATION SCHEME: DE= (IN A(S)=W(S)/(DE-DELTA(S)) I.E. IN THE FORMATION OF A NEW WAVE FUNCTION. 0

USE DE DEPENDING ON THE METHOD USED. (IOp(5)). FOR METHOD = 0,1->.DE = W(0)/A0. FOR METHOD .GT. 1.->DE = 0. NOTE THAT FOR PERTURBATION METHODS (METHOD=2,3,4,5) DE IS NOT REALLY NEEDED SINCE THE WAVE FUNCTION FORMED NEVER GETS USED. 1

W(0)/A0. ALWAYS.

2

0. ALWAYS.

IOp(9/19)

EXTRAPOLATION. 0

Default: CI using old extrapolation, QCISD using RLE.

1

Do not extrapolate.

2

Use BFGS.

3

Use DIIS.

4

Use old extrapolation for CI.

5

Use RLE.

00

Use A as guess for Z.

10

Use scaled A as guess for Z.

100 Reset RLE for Z iterations. IOp(9/20)


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Whether to update the total energy with the MP2 energy in L901. 0

Yes.

1

No (used in HF second derivative calculations).

IOp(9/21)

Guess for eigenvector of y-matrix in link 902. IOp(9/22)

Conversion factor in L919. -1

Read in factor in format D20.10.

0

Default of 10**-8.

N

10**-N.

IOp(9/23)

Localization of orbitals in L919. 0

None.

1

Localize occupieds.

2

Localize virtuals.

3

Localize both.

00


10

Choose configurations by simple truncation.

20

Read in configurations.

000 Rettrup-Davidson RPA. 100 Jorgensen-Linderberg Hermetian RPA. 0000 Out-of-core method. 1000 In-core method.


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00000 Singlet states. 10000 Triplet states. Maximum order of perturbation theory in L921 and L922. Correction to CIS in L914: 0

No

-2

CIS-DFT (in primitive energy code)

-1

CIS-MP2 (in primitive in-core program)

1

CIS-MP2 (in MO Basis disk routine)

2 CIS-DFT (in production code). The functional is given by IOp(17). IOp(9/25)

PRINT PAIR CONTRIBUTION AND WEIGHT TO CORRELATION ENERGY 0

NO

1

YES, AT THE END OF CI

2

YES, AT EACH CYCLE

3

YES, AT ONE CYCLE GIVEN BY INPUT (I3)

4

YES, AT FIRST CYCLE AND AT END

IOp(9/26)

NORMALIZATION OF THE WAVEFUNCTION 0

NORMALIZED TO A(0)=1.

1

SUM(S) A(S)**2 = 1

(ALL S)

NOTE: PERTURBATION THEORETICAL RESULTS ARE VALID WITH NORM=0 ONLY IOp(9/27)


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Maximum amount of disk to use in L906: -1

No disk; force fully direct method by default.

0

Use as much disk as needed for a single pass.

N

N words.

IOp(9/28)

PRINTING OF DOMINANT CONFIGURATIONS. 0

Default (print coefficients 0.1 and above).

-3

Do not print coefficients.

-2 -1

Print all coefficients every iteration. Scan the 'A' vector and print all coefficients.

N Scan the 'A' vector and print all coefficients having coefficients greater than 0.0001*N. IOp(9/30)

Calculation of the one-particle density matrices: 00

Default (21 for CI, 22 otherwise).

1

Compute the CI one-particle density matrix.

2

Do not form the CI one-particle density matrix.

10 Compute the density correct to second order (NOT the same as the density corresponding to the MP2 energy). 20

Do not compute the density correct to second order.

IOp(9/31)

Print vectors and matrices in 902 and 918 0/1 no/yes. IOp(9/36)

Compute the T1 Diagnostic of T.J. Lee


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IOp(9/37)

Maximum dimension for the QCISD extrapolation. For BFGS extrapolation,default size is ten. The maximum dimension is 25. Same for DIIS extrapolation. IOp(9/38)

Minimum dimension for the QCISD extrapolation. For BFGS extrapolation, the smallest dimension one and the default is three. The maximum dimension is eight. For DIIS extrapolation, the only dimension is IOp(39) L913: Type of convergence test 0 - Default: energy and gradient. 1 - Converge on energy only 2 - Converge on energy and gradient 3 - Converge on gradient only Convergence on gradient is for extrapolated CI and QCISD procedures. L914: Pick out guesses from restart file or othogonalize guesses to the states already on restart file (IOp49 must be set to 1 or 2 for this option to be valid) 0

Just take guess from restart file

N

Make N additional orthogonal guesses to those present

-1

Read which N states to use (free format integers)

*** WARNING: The states on the restart file MUST be orthogonal to the convergence requested (ie; the previous job indicates wavefunction not just expansion vectors has converged). IOp(9/40)

Reference wavefunction for MP2 in L906:


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0

Default (HF).

1

CASSCF.

2

HF.

THRESHOLD FOR PRINTING EIGENVECTOR COMPONENTS in L914: 0

ITHR = 1

N

ITHR = N

WHERE THRESHOLD = GFLOAT(10)**(-ITHR) IOp(9/41)

L914: NUMBER OF STATES TO SEEK WHENFOR USING DAVIDSON, OR NUMBER OF STATES TO PRINT OUT INFORMATION WHEN USING DODIAG: 0 N -N

DEFAULT TO 2 LOWEST N STATES READ IN PRINCIPLE COMPONENT OF N GUESSES (DAVIDSON). FORMAT I5 ON LAST CARD BEFORE EOF

IOp(9/42)

METHOD AND MATRIX BLOCKS TO WORK ON in L914 (See below) -NNN

Mapped directly to NNN below.

1

AO basis.

2

In-core. Mapped to 2, 222, or 20 as appropriate.

3

MO Mapped to 3, 333, or 30 as appropriate.

0

DEFAULT IS: 3 (RHF REFERENCE STATE)

333

(UHF REFERENCE STATE)

BITS

MATRIX

1

AA,BB

METHOD --


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NYI

10 AB

NYI

|-> FORCE DAVIDSON IN A.O. BASIS

100 BA

--

2

AA,BB

--

20

AB

|-> FORCE DODIAG TO FIND ALL ROOTS

200

BA

--

3

AA,BB

--

30

AB

|-> FORCE DAVIDSON IN M.O. BASIS

300

BA

--

IOp(9/43)

How to handle subsequent Davidson Iterations in L914: 0 If this is not a restart, then half the number of states at the second iteration. If this is a restart, then don't. 1

Force Davidson to half the number of states at iteration 2.

2

Force Davidson not to half the number of states at iteration 2.

IOp(9/44)

Density matrix control for filling RWF 633 in L914: 0

Same as 2

1

Do densities of each excited state

2

Do densities and transition densities from ground

3 Do densities, transition densities from ground, and transitions densities among all excited states IOp(9/45)

Debug option for comparing previous results in L914. 0

Use Phycon to convert to eV's


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1

Use old conversion to eV's

IOp(9/46)

Control of Davidson Convergence in L914: <0

Use Ortvec convergence only

0

Converge on the number of roots - IOp(41)

N

Converge on Ci Amplitudes for N lowest states

IOp(9/47)

Control of Davidson Iterations in L914: 0

Usual

1

Don't do any iterations (guess=print)

2

Stop after first iteration

IOp(9/48)

RESTRICTION ON TYPES OF ROOTS (DAVIDSON RHF ONLY) 0

GUESS ONLY SINGLETS

1

Same as 0

2

GUESS BOTH SINGLETS AND TRIPLETS

3

GUESS ONLY TRIPLETS

NOTE: A SINGLET GUESS MAY RESULT IN A TRIPLET ROOT IN EXTREME CASES (SMALL NUMBER OF ROOTS SOUGHT) IOp(9/49)

INITIAL GUESS VECTORS 0

MAKE A GUESS BASED ON DIAGONAL ELEMENTS

1

USE GUESS VECTORS ALREADY ON RWF


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2

USE GUESS VECTORS ALREADY ON CHK

3

GENERATE GUESSES FROM CIS DENSITIES on CHK

4

GENERATE GUESSES FROM CIS DENSITIES on RWF

IOp(9/60-62)


1 to force TDHF in L914. IOp(9/71)

Whether to do an extra iteration after Davidson convergence. 0

Default (No).

1

Yes.

2

No.

IOp(9/72)

Whether to computed frequency-dependant polarizabilities. 0

No.

1

Yes.

IOp(9/73)

Whether to do non-equilibrium solvation in L914: 0

Default (Yes, if doing excited states, no for stability).

1

Yes.

2

No, use equilibrium.

IOp(9/74)

Over-ride default choice of frequency dependence of the XC functional in L914:


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0

Use default value.

N

Use form N (see IOp(88) in overlay 5).

IOp(9/75)

Whether to save amplitudes and integrals in L906: 0

Save only if doing second derivatives (SqS12 set).

1

Save amplitudes.

2

Save amplitudes and integrals.

IOp(9/81)

Minimum number of Pair Natural Orbitals (PNO) to start the extrapolations from, NStart. 0

Default - 5 (assuming CBS-4 calculations, i.e. 6-31+G(d',p')).

-N

Calculate the extrapolated value at N only.

N

Get the lowest energy value between CBS(N) and CBS(NVirt).

IOp(9/82)

Convergence tolerance for CBS localization. 0 N

Use the default. Use 10**(-N)

IOp(9/83)

Localization Method. -1

No localization.

0

Default (4).

1

Boys.

2

Population

3

Boys+Population.


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4

Minimal population.

5

No localization.

10

Do 2nd order.

100 Localize core even if not needed. IOp(9/84)

Save CBS localized orbitals to RWF (this will overwrite the SCF orbitals, intended for visualization). 0

No, don't save (default).

1

Yes, save them.

IOp(9/85)

Flags for SAC-CI IOp(9/86)

Whether L906 should generate data compressed to active atoms during mp2 frequencies with ONIOM: 0

Default (2).

1

Yes.

2

No.

Overlay 10 5 6 7 8 9 10 11 13 14 15 16 17 18 19 20 21 22 28 29 30 31 32 45 46 47 48 60 61 62 63 72 72 74 75 76 77 78 79 IOp(10/5)

CALCULATION OF FIRST DERIVATIVES OF POST-SCF ENERGIES. Only implemented for closed-shell and UHF. 0

NO


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1

CALC. D E(MP2) / D R

2

CALC. D E(CID) / D R

3

CALC. D E(CISD) / D R

4

Calc. D E(CIS) / D R

5

Calc. D E(CCD) / D R

6

Calc. D E(CCSD/QCISD) / D R

7

Calc. D E(BD) / D R

8

Calc. D E(MP3) / D R

9 00

Calc. D E(MP4) /D R Default CPHF usage (Z-vector unless HF D2E)

10

Full 3*NAtoms CPHF.

20

Z-Vector method.

30

Test Z-Vector using full CPHF.

000

Default derivative processing - just set up here unless doing HF 2nd derivatives

simultaneously. 100 Compute F1 and S1 derivative terms here. 200

Don't process any derivative terms here. Setup for external processing of W and Z.

IOp(10/6)

Calculation of the second derivatives of the SCF energy. Available for RHF and UHF. Partially coded but NYI for high-spin ROHF. 0

No.

1

Yes, do D2 E(SCF) / D R(I) D R(J)

2 Setup For MP2 2nd Derivatives (i.e. No contributions to the force constants are done here). 00

Default: use new Px/Wx digestion code if possible, save as little data as possible.


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10

Use old Px/Wx digestion code.

20

Use new Px/Wx code but save both S1 and F1 over MOs.

30

Use new Px/Wx code and don't save S1 but do save F1.

100

Compute dipole derivatives using only electric field CPHF and F(x) matrices.

1000 Set up for GIAO MP2 calculation. 10000 Do DFT 3rd derivatives. 20000 Do hyperpolarizabilities for second-harmonic generation. IOp(10/7)

RMS CONVERGENCE ON C1(I,A) contributions. The max element is tested against 10* this value. 0

Default: 1.D-9, except 1.D-11 for Z-Vector CPHF. N

1.D-N.

IOp(10/8)

Selection of linear equation solution method. 0


1

Expand each variable in a separate expansion space.

2 Solve all equations together, possibly reverting to the old (one variable at a time) method in the secondary solution. 3

Invert the A matrix directly.

IOp(10/9)

Whether to compute Born-Oppenheimer corrections. 0

No.

1

Yes.

IOp(10/10)


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Control of CPMCSCF during avoided crossing/conical intersection searches. IOp(10/11)

Largest matrix for direct inversion in LinEq2. 0

Default invert directly if there is enough memory.

-1

Always use DIIS, never invert directly.

N

N.

IOp(10/13)

The nature of the perturbation(s). 0


IJKL Nuclear Lth order. Electric field Kth order. Magnetic Field Jth order. Nuclear magnetic moment Ith order. IOp(10/14)

Whether to update dipole and polarizability derivatives. 0

Default (yes if IOp(5).eq.0).

1

Update dipole.

2

Don't update dipole

10

Update polarizability.

20

Don't update polarizability.

100 Force 2nd order cphf for polarizability derivatives. IOp(10/15)

What to do with expansion vectors from the linear equations. 0 Default (=1 if IOp(8)=1 and electric field only and no derivatives are being computed, =2 otherwise). 1

Save vectors at end.


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2

Delete vectors at end of each CPHF.

3

Pass vectors from 1st to 2nd order CPHF, but delete at end of link.

00

Default (Use old vectors if available).

10

Use old vectors if available.

20

Ignore old vectors.

Note that because of numerical instabilities in the simultaneous solution method, reusing old expansion vectors for new B vectors can reduce accuracy. This may be acceptable in the electric field second order CPHF, which is used only for one term in polarizability derivatives and for which the accuracy requrirements are less stringent, but use of electric field expansion vectors for nuclear coordinate CPHF can cause errors of up to 1 cm**-1 with current tolerances. This option is normally used to pass 1st order electric field results to the second invokation of 1002 during frequency calculations. IOp(10/16)

Convergence in secondary linear equations (only for simultaneous solution). 0

Use standard machine tolerance (MDCutO) on maximum and rms.

N

Convergence is 10**(-N) for max and rms.

IOp(10/17)

Frozen-core: 0

Default (use AO 2PDM for Lagrangian only if orbitals are frozen in /Orb/).

1

Do C1, C2, S1, and S2 off the AO 2PDM.

2 Convert /Orb/ to full, for debugging frozen-core with integrals over the full window. 3

Save as 2, but leave the full version of /Orb/ on the disk.

IOp(10/18)

Whether to do correct or approximate CPHF. 0

CPHF is done correctly.


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1 The A-matrix is neglected, and hence the U-matrices are set equal to the Bmatrices (i.e., uncoupled Hartree-Fock is used). 2

The U-matrices are set to zero.

3 Only a single set of products AX are computed, independent of convergence criteria. Simultaneous solution is implied. IOp(10/19)

Whether overlap (S1) terms must be included. 0

Default (yes).

1 2

Yes. No.

Note that the appropriate rwf (588) must be present in any case. IOp(10/20)

How to handle 2e integral contributions: 0

Default (decide on the fly).

1

Read the 2e integral files, MO if possible.

2

Compute the 2e integrals when needed.

3 direct.

Force use of AO integrals, even if MO ones are available, i.e. force AO or

4

Don't use integrals, even if present.

MNx

Use option MN in control of 2e integral calculation.

IOp(10/21)

Whether to store Uai, Spq, and full MO Fock matrix derivatives in permanent rwfs. 0

Default (No).

1

Yes. Disables use of symmetry to reduce the size of the CPHF problem here.


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2

No.

10

Save magnetic MO deriviatives.

IOp(10/22)

Which multipole (electric field) perturbations to include? Only used if J part of IOp(13) is non-zero. 0

Default. Uniform electric field (dipole) only.

1

Dipole (uniform electric field).

2

Quadrupole (electric field gradient, all 6 cartesian components.

3

Octopole.

4

Hexadecapole.

IOp(10/28)

State for CPMCSCF: 0 N

Default (ground state). Nth excited state.

IOp(10/29)

Use of rafinetti integrals during direct SCF. -N All integrals done as Raffenetti if there are N or more matrices; all as regular if there are less than N. 0

Default: let FoFDir decide.

1

All integrals are done as regular integrals.

N Integrals with degree of contraction greater than or equal to N are done are regular integrals. IOp(10/30)

In-core storage of 2e integrals: 0

Default - do if possible in direct calculation.


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1

Force in-core storage; recover ints if available on rwf 610.

2

Force recomputation.

IOp(10/31)

Whether to use symmetry to reduce the number of CPHF equations: 0

Default (yes).

1

No.

2

Yes.

IOp(10/32)

Whether to apply interchange in link 1004: 0

Default (No).

1

Yes.

2

No.

Whether to read D2E file in link 1003: 0

Default (No).

1

Yes.

2

No.

IOp(10/45)

Type of Gauge Transformations to perform to calculate the current distribution within the molecule, and hence the molecule's other magnetic properties. -1

None.

0

Default (16 if doing magnetic CPHF).

1 Use single gauge origin - the gauge used to calculate the angular momentum perturbed wavefunctions. 2 Use IGAIM method - gauge origin coincident with the nucleus of the integrated atomic regions.


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4

Use CSGT method.

8

Use single gauge origin - the coordinates of which are read in (in Angstroms).

16

Use GIAOs.

IOp(10/46)

Whether to calculate dipole and rotational strengths (VCD). 0

No (Default)

1

Yes

2

No

3

Do only optical rotational strength.

IOp(10/47)

Whether to do spin-spin coupling constants. 0

Default (No)

1

Yes.

2

No.

IOp(10/48)

Whether to operate only over perturbations involving active atoms. 0

Default (For nuclear, compress if overlay 11 did).

1

Compress.

2

Don't compress.

3

Don't compress, but blank contributions for inactive atoms.

IOp(10/60-62)



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Changing defaults. 0 Default: Use FMM if turned on globally, use more aggressive cutoffs in Xc integration, use more aggressive cutoffs in integrals and FMM unless doing NFx. 1


2

Use FMM if turned on globally.

10

Use global cutoffs.

20

Use local, lower cutoffs suitable only for CPHF/CPKS.

IOp(10/72)

Whether to do frequency-dependent properties: 0 Default (No, unless both electric and magnetic properties are requested). 1

No.

2

Yes.

3

Yes, read in frequencies.

4

Yes, with formalism for frequency-dependent XC response.

00 Update frequency-dependent property file if frequency-dep. calculation is performed. 10

Update regardless.

20

Do not update.

IOp(10/73)

Maximum number of CPHF cycles. 0

Default (1000). N

N.

IOp(10/74)

Whether to do non-equilibrium solvation.


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0

Default: Only if frequency-dependent.

1

Yes.

2

No.

IOp(10/75)

Print during NMR. 0

Default (1).

1


2


IOp(10/76)

Over-ride general choice of exchange-correlation frequency dependence. 0

Use global value for this job step.

N

Use type N (see IOp(88) in overlay 5).

IOp(10/77)

Test CPHF results by checking the CPHF equations using the complete MO Fock and density derivatives. 0

Default (No).

1

Yes.

2

No.

IOp(10/78)

Whether to solve CPHF equations for MOD method. 0

Default (1).

1

Canonical MO derivatives.

2

MOD orbital derivatives.

00

Default (20).


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10

Solve using DiagD.

20

Solve with SimEqn.

IOp(10/79)

Stop the link at selected points, for testing restarts. MNN

Stop at pass M (default 1), restart point NN.

Overlay 11 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 26 27 28 29 30 31 32 33 39 40 41 42 43 45 46 53 60 61 62 63 70 71 75 IOp(11/5)

IFWRT: DERIVATIVE INTEGRAL WRITE OPTION. 0

DO NOT PRODUCE A D2E FILE.

1

PRODUCE A D2E FILE.

IOp(11/6)

IFHFFX: WHETHER OR NOT TO CONTRACT INTEGRAL DERIVATIVES WITH HARTREE-FOCK DENSITY MATRIX TERMS TO PRODUCE HARTREE-FOCK TWO-ELECTRON CONTRIBUTION TO THE FORCES. 0

NO.

1

YES.

2 Yes, also contracted electric field density matrix derivatives to form the twoelectron integral derivative contribution to the polarizability derivatives. IOp(11/7)

IFTPDM: WHETHER OR NOT TO CONTRACT INTEGRAL DERIVATIVES WITH A 'READ-IN' TWO-PARTICAL DENSITY-MATRIX. 0

NO.

1

YES.


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2

Yes, but generate and write out the HF 2PDM here for debugging purposes.

IOp(11/8)

IFF1: WHETHER OR NOT TO COMPUTE F1 OVER AO'S. 0

No.

1

Yes.

IOp(11/9)

IDOUT: FIRST-DERIVATIVE OUTPUT OPTION. CONTAINS I2*100+I1*10+I0. I0 0 1

WHETHER OR NOT TO USE THE CONTENTS OF IRWFX. NO. YES, IF NOT THERE, MERELY SET THE ARRAY TO ZEROES.

I1 PROCESSING OF TWO-ELECTRON HARTREE-FOCK CONTRIBUTIONS. 0 NONE. 1 TAKE HF CONTRIBUTIONS FROM FX1 (A LA IFHFFX). 2 TAKE HF CONTRIBUTIONS FROM F1 (A LA IFF1). (forms the 1/2(F-H) term in link 1110). 3 Form 1/2(F+H) term in link 1110. I2 0 1

PROCESSING OF TPDM CONTRIBUTIONS. NONE. ADD IN CONTENTS OF FX2.

IOp(11/10)

Whether to compute Fock matrices, Lagrangian, and SCF energy in L1110: 0

No.

1

Yes.

IOp(11/11)

Control of integral derivative algorithm: 0

Default

use IsAlg to decide.

2

Scalar Rys SPDF.


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3

Illegal here.

4

Illegal here.

5

Illegal here.

6

Illegal here.

7

Illegal here.

8

Illegal here.

9

Illegal here.

10

Illegal here.

11 12

Illegal here. FoFDir: Prism spdf.

13

Illegal here.

IOp(11/12)

Selection of 1PDM in L1102 and L1110: 0

Usual SCF density.

N Use generalized density number N for both the one-electron integral derivatives and the corresponding 2PDM terms. IOp(11/13)

Flags for L1112: 0

Default for Ix==>Sx (same as 1).

1

Use Ix.

2

Use L(x) and Ux*I.

00

Formation of Ux*I*T terms, default, same as 1.

10

N**4 I/O algorithm.

20

Old gOV3 I/O algorithm.


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000 Formation of Fx*T*T terms: default is to choose based on available memory. 100 Force O2V2 method. 200 Use (2g+O)V2 memory algorithm even if O2V2 memory is available. 300 Force old N**5 I/O algorithm. 0000 Default Ix*T algorithm (1) 1000 Force new algorithm. 2000 Force old algorithm. IO(11/14)

The nature of the perturbation(s). 0 Default (1st order nuclear and electric field). IJK Nuclear Kth order. Electric field Jth order. Magnetic Field Ith order. IOp(11/15)

Controls output of derivatives to rw-files. i4*10000+i3*1000+i2*100+1i*10+i0 i0 .ne.0 load fxyz from rw-files if it exists. i1 .eq.1 calculate nuclear contribution. i2 .ne.0 calculate one-electron contribution. i3 .ne.0 controls output of 'old' format. i4 .ne.0 forces out-of-core algorithm IOp(11/16)

Mode of operation of L1102. 0

Default: compute dipole derivative matrices only.

1

Also compute dipole derivative integral contribution to the HF dipole derivatives.

10

Also compute HF contribution to the dipole moment.


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IOp(11/17)

Frozen-core in L1111: 0

Default (use AO 2PDM for Lagrangian only if orbitals are frozen in /Orb/).

1

Do C1, C2, S1, and S2 off the AO 2PDM.

2 Convert /Orb/ to full, for debugging frozen-core with integrals over the full window. 3

Save as 2, but leave the full version of /Orb/ on the disk.

10

Form the derivative integral contribution to the Lagrangian as well. This is stored on disk as RL(NBasis,NBasis,NAt3,IOpCl+1) in rwf 1001.

IOp(11/18)

Save AO 2PDM from L1111. 0

No.

N

Save the AO 2PDM on rwf N. It is (NTT,NTT) and includes factors (2-Delta(ij))(2-Delta(kl)). It doesn't include any normalization factor.

IOp(11/19)

Whether to delete MO integrals after 1112: 0

Default (Yes).

1

Yes.

2

No.

IOp(11/20)

How to handle 2e integral contributions in L1112: 0


1

Read the 2e integral files, MO if possible.

2 Compute the 2e integrals when needed. This link must have been built with the non-dummied version of FoFDir and associated integral routines.


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3

Force use of AO integrals, even if MO ones are available.

MNx Use option MN in control of 2e integral calculation. IOp(11/21)

Size of buffers for integral derivative file. 0 N

Default (Machine dependent; see DSet2E). N integer words.

IOp(11/22)

In-core option in 1112. IOp(11/23)

Use of rafinetti integrals during direct term in L1112: -N All integrals done as Raffenetti if there are N or more matrices; all as regular if there are less than N. 0

Default: let FoFDir decide.

1

All integrals are done as regular integrals.

N Integrals with degree of contraction greater than or equal to N are done are regular integrals. IOp(11/24)

Output of 1102: 00

Default (01).

1

Contract with density matrix to form dipole derivative contributions.

10

Store dipole derivative matrices on disk.

IOp(11/26)

PROGRAM ACCURACY OPTION. 0

DO INTEGRALS ECOMOMICALLY TO 10**(-10) ACCURACY.


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1

'TEST' OPTION BYPASS CUTOFFS.

IOp(11/27)

INTEGRAL RETENTION PARAMETER. 0 N

RETAIN INTEGRALS GE 10**(-10) IN THE D2E FILE (IF SELECTED) AND/OR 10**(-10) IN THE INTEGRAL HEAP IF IFF1=1 AND MODE=2. RETAIN INTEGRALS GE 10**(-N).

IOp(11/28)

Location or generation of MO 1 and 2 PDMs for L1111: -7

Compute QCISD 2PDM

-6

Compute CCD 2PDM

-5

Compute CIS 2PDM

-4

Compute CISD 2PDM.

-3

Compute CID 2PDM.

-2

Compute MP2 2PDM.

-1

Compute HF DMs.

0

Default (RWFs 626, 627, and 628).

N

RWFS N (1PDM), N+1 (W), and N+2 (2PDM).

IOp(11/29)

What to do: 1

Transform 1PDM and Lagrangian from MO to AO.

10

Transform 2PDM from MO to AO.

100

Sort AO 2PDM into shell order. If back transformation has not been requested, the double-length AO 2PDM is expected in file 1001. The sorted 2PDM is left in file 602.


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200 2PDM

Form the contribution of the 2PDM to the forces right here. Note that if the

is also to be left behind, it will be over 6d/10f and have the HGP d and f scale factors in it. 1000 10000

Suppress writing alpha, beta, and spin density rwfs. Form and sort the 2PDM derivatives rather than the 2PDM.

20000

Generate replicated 2PDM copies for testing.

IOp(11/30)

What to compute using integrals or D2E file. 1

Energy.

10

Gradient.

IOp(11/31)

Whether to use symmetry in Rys integral derivatives in L1110: 0

Yes.

1

No.

IOp(11/32)

Whether to do 2PDM or just Lagrangian in L1111: 0

Compute Full Gradient

1

Compute Full Gradient (Same as Default).

2

Compute Density Only.

3

Compute Density and W Only.

4

Compute 2PDM only, no density or W.

IOp(11/33)

IPRINT IOp(33) 0

PRINT OPTION.

NO PRINTING.


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1

PRINT COMPUTED FIRST-DERIVATIVES.

2

PRINT F1 MATRICES.

IOp(11/39)

Compression of derivative matrices: 0

Default (2).

1

Compute over active atoms only.

2

Compute over the full list of atoms.

3

Compute over the full list of atoms, but blank contributions for inactive atoms.

IOp(11/40)

Neglect of integrals (only option 1 works in Overlay 10): 0

Keep all integrals.

1

Neglect four center integrals.

2

Neglect three center two-electron integrals as well.

3


10

Neglect three center one-electron integrals.

20


30


IOp(11/41)

NDDO flag. 0

Evaluate usual integrals.

1

Evaluate matrices in the NDDO approximation.

IOp(11/42)

Compressed file formats.


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0

Default: compressed.

1

Force expanded form.

2

Force compressed form.

3

Compressed Sx but separate H1 and F1.

IOp(11/43)

Batching in overlay 11. 0

Default, smallest possible number of passes.

1

Do at least one pass, but using the out of core algorithms.

N Do at least N passes. For Rys in L1110, N is 0/1/2 for default/in-core/out-of-core. IOp(11/45)

Force NAt3 instead of NAt3+3 storage of matrices (for debugging): 0

No.

1

Yes.

IOp(11/46)

Whether to include orbital rotation gradient terms for SAC-CI. 0

No.

1

Convert 1PDM to canonical representation.

2

Save gradients to disk, needed for non-canonical methods.

IOp(11/53)

Convert forces over shells to field-dependent dipole and forces over atoms (for debugging): 0

No.

1

Yes.


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IOp(11/60-62) IOp(11/60-62)



Use global default.

1


IOp(11/70)

Whether to allow cavity to move in PCM derivatives. 0

Default (No).

1

Yes.

2

No.

IOp(11/71)

Debugging option for DBF derivatives: 0

Normal processing.

1

Ignore fitting density and just process real density in L1110.

2

Copy fitting density over real density. Only works using 1C shell pairs for the density basis and only with cartesian functions.

IOp(11/75)

Print during NMR. 0 Default (1). 1


2



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Overlay 9999 5 6 7 8 9 10 11 12 13 14 15 16 17 18 33 IOp(9999/5)

CONTROLS HANDLING OF THE CHECKPOINT FILE: 0

THE RUN IS AN OPTIMIZATION OR FREQUENCY RUN, SO BOTH THE PERMANENT AND RESTART FILES ARE IN THE CHECKPOINT FILE. DELETE THE RESTART INFORMATION IF THE RUN IS FINISHING NORMALLY (I.E. IF THE ERROR TERMINATION ILSW BIT IS NOT SET).

1

THE RUN IS NOT AN OPTIMIZATION. SAVE THE PERMANENT INFORMATION (MOS, BASIS SET INFO ETC.) ON THE CHECKPOINT

FILE. 2 Do not write anything to the checkpoint file. 3

Archive data from the checkpoint file.

4 Restart a multi-step job, recovering data from the checkpoint file and figuring out which job step to run next and whether it needs restart if an optimization or numerical frequency. 5generated Saveindata the chk file, but don't remove extra data (i.e., if a new version was not thison step). IOp(9999/6)

Controls output of Fortran unformatted files for other programs: 0

No PolyAtom output.

1

PolyAtom output in working precision to Fortran unit 8.

00

No GVB2P5 trans file.

10

GVB2P5 trans file to unit 14.

100

WFN file output

200

WFN file output with magnetic orbital derivatives.


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300

WFN file output with GIAO magnetic orbital derivatives.

1000

Use natural orbitals in WFN file

IOp(9999/7)

Controls whether MOs are written to the polyatom integral tape in LANL style. 0

No.

1

Yes.

IOp(9999/8)

Reading temperature, pressure, and isotopes during multi-step energy calculations: 0


1

No, use defaults.

2

Yes.

IOp(9999/9)

Controls archiving of dipole moment and other electic field derivatives, except for archiving from the chk file. 0

Archive all as is.

1

Archive all, but rotates to z-matrix orientation first.

2

Don't archive.

IOp(9999/10)

Controls punching of assorted information (i.e., formatted output to unit 7). 0

Nothing.

1

Title.

2

Atomic numbers and coordinates in format (I3,3D20.12).

4 Derivatives (forces and force constants) in format (2X,3D20.12). These are in the Z-matrix orientation.


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8

The archive entry. This is independant of normal archiving to the main file.

16

An input deck for HONDO.

32

The molecular orbitals, in format suitable for guess=cards, in the standard

orientation. 64 A GAMESS input deck. 128

The natural orbitals generated by link 601.

256

A WFN file for PROAIMS.

512

Use natural orbitals in WFN file.

1024

Output hyperfine tensors as input to Pickett's program (sent to the output file).

2048

Read a list of atoms to use in the Pickett input.

IOp(9999/11)

Which type of database to update: 0

Default (3).

1

Old format.

2 3

New format. Both.

IOp(9999/12)

Flag for coordinate optimization: 0

No.

1

Yes; remove /ZMat/ and /ZSubst/ from the rwf and chk files.

IOp(9999/13)

Whether this is the end of the job step: 0

Default (Yes).

1

Yes.


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2

No.

3

Go back to Link 1.

IOp(9999/14)

Whether to attempt to express the final optimized structure in terms of the input z-matrix: 0

Yes if there are 20 or fewer atoms.

1

Yes.

2

No.

3

Yes, and update rwfs.

IOp(9999/15)

Act as though in multi-step job type IOp(15). IOp(9999/16)

Treat the job as type (Info(7)) given by IOp(16). IOp(9999/17)

Treat as MSJDon=IOp(17) step in a multi-step job. IOp(9999/18)

How many virtual orbitals to include in the WFN file. 0

Default (None).

-1

Include all virtual orbitals.

N

Include N virtual orbitals.

IOp(9999/33)

CONTROLS DEBUG PRINT: 0

NO DEBUG PRINT.

1

DEBUG PRINT.


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IRC This method keyword requests that a reaction path be followed [151,152]. The initial geometry (given in the molecule specification section) is that of the transition state, and the path can be followed in one or both directions from that point. By default, the forward direction is defined as the direction the transition vector is pointing when the largest component of the phase is positive; it can be defined explicitly using the Phase option. The geometry is optimized at each point along the reaction path such that the segment of the reaction path between any two adjacent points is described by an arc of a circle, and so that the gradients at the end points of the arc are tangent to the path. The path can be computed in mass-weighted internals, Cartesians or internals coordinates. By default, an IRC calculation steps 6 points in mass-weighted internals in the forward direction and 6 points in the reverse direction, in steps of 0.1 amu1/2 bohr along the path. IRC calculations require initial force constants to proceed. You must provide these to the calculation in some way. The usual method is to save the checkpoint file from the preceding frequency calculation (used to verify that the optimized geometry to be used in the IRC calculation is in fact a transition state), and then specify IRC=RCFC in the route section. The other possibilities are providing the force constants in the input stream (IRC=FCCards) and computing them at the beginning of the IRC calculation (IRC=CalcFC). Note that one of RCFC, CalcFC, CalcAll and FCCards must be specified. IRC calculations accept Z-matrices or Cartesian coordinates as molecule specifications and uses these coordinates in following the reaction path. You should specify alternative isotopes for IRC jobs using the standard method. IRC studies are not currently archived. PATH SELECTION OPTIONS Phase=( N1 N2 [ N3 [ N4]])

Defines the phase for the transition vector such that "forward" motion along the transition vector corresponds to an increase in the specified internal coordinate, designated by up to four atom numbers. If two atom numbers are given, the coordinate is a bond stretch between the two atoms; three atom numbers specify an angle bend, and four atoms define a dihedral angle.


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Forward

Follow the path only in the forward direction. Reverse

Follow the path only in the reverse direction. ReadVector

Read in the vector to follow. The format is Z-matrix (FFF(I), I=1,NVAR), read as (8F10.6). MaxPoints= N

Number of points along the reaction path to examine (in each direction if both are being considered). The default is 6. StepSize= N

Step size along the reaction path, in units of 0.01 amu1/2-Bohr. The default is 10. MaxCyc= N

Sets the maximum number of steps in each geometry optimization. The default is 20. COORDINATE SYSTEM SELECTION OPTIONS MassWeighted

Follow the path in mass-weighted internal (Z-matrix) coordinates (which is equivalent to following the path in mass-weighted Cartesian coordinates). MW is a synonym for MassWeighted . This is the default. Internal

Follow the path in internal (Z-matrix) coordinates without mass weighting Cartesian

Follow the path in Cartesian coordinates without mass weighting.

RCFC

Specifies that the computed force constants in Cartesian coordinates from a frequency calculation are to be read from the checkpoint file. ReadCartesianFC is a synonym for RCFC. CalcFC

Specifies that the force constants be computed at the first point. CalcAll

Specifies that the force constants be computed at every point.


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FCCards

Reads the Cartesian forces and force constants from the input stream after the molecule specifications. This option can be used to read force constants recovered from the Quantum Chemistry Archive using its internal FCList command. The format for this input is: Energy (format D24.16) Cartesian forces (lines of format 6F12.8) Force constants (lines of format 6F12.8)

The force constants are in lower triangular form: (( F ( J,I ) ,J=1 ,I ) ,I=1, NAt 3), where NAt3 is the number of Cartesian coordinates. If both FCCards and ReadIsotopes are specified, the masses of the atoms are input before the energy, Cartesian gradients and the Cartesian force constants. OPTIMIZATION ALGORITHM-RELATED OPTION VeryTight

Tightens the convergence criteria used in the optimization at each point along the path. This option is necessary if a very small step size along the path is requested. RESTART OPTION Restart

Restarts an IRC calculation which did not complete, or restarts an IRC calculation which did complete, but for which additional points along the path are desired.

HF, all DFT methods, CIS, MP2, MP3, MP4(SDQ), CID, CISD, CCD, CCSD, QCISD, CASSCF, and all semi-empirical methods.

Opt, Scan, IRCMax

The output for each step of an IRC calculation is very similar to that from a geometry optimization. Each step is introduced by this banner line (where "IRC" has replaced "Grad"): IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC


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As the optimization at each point completes, the optimized structure is displayed: Optimization completed. -- Optimized point # 1 Found. ---------------------------! Optimized Parameters ! ! (Angstroms and Degrees) ! --------------------------------------! Name Value Derivative information (Atomic Units) ! -------------------------------------------------------------------! CH1 1.3448 -DE/DX = 0.0143 ! ! HH 0.8632 -DE/DX = -0.0047 ! ! CH2 1.0827 -DE/DX = 0.0008 ! ! HCH 106.207 -DE/DX = -0.0082 ! -------------------------------------------------------------------RADIUS OF CURVATURE = 0.39205 NET REACTION COORDINATE UP TO THIS POINT = 0.09946

Once the entire IRC has completed, the program prints a table summarizing the results: -------------------------------------------------------------------SUMMARY OF REACTION PATH FOLLOWING: (Int. Coord: Angstroms, and Degrees) -------------------------------------------------------------------ENERGY RX.COORD CH1 HH CH2 1 -40.16837 -0.49759 1.54387 0.73360 1.08145 2 -40.16542 -0.39764 1.49968 0.74371 1.08164 3 -40.16235 1.45133 0.76567 1.08193 4 -40.15914 -0.29820 -0.19914 1.39854 0.80711 1.08232 5 -40.15640 -0.09946 1.34481 0.86318 1.08274 6 -40.15552 0.00000 1.30200 0.91500 1.08300 7 -40.15649 0.09990 1.26036 0.96924 1.08330 8 -40.15999 0.19985 1.21116 1.03788 1.08349 9 -40.16486 0.29975 1.16418 1.10833 1.08353 10 -40.16957 0.39938 1.12245 1.18068 1.08328 11 -40.17324 0.49831 1.09260 1.25158 1.08276 -------------------------------------------------------------------TOTAL NUMBER OF GRADIENT CALCULATIONS: 28 TOTAL NUMBER OF POINTS: 10 AVERAGE NUMBER OF GRADIENT CALCULATIONS: 2.80000

The initial geometry appears in the middle of the table (in this case, as point 6). It can be identified quickly by looking for a reaction coordinate value of 0.00000.

IRCMax


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Performs an IRCMax calculation using the methods of Petersson and coworkers [168,169,170,171,172,173,174,175,176]. Taking a transition structure as its input, this calculation type finds the maximum energy along a specified reaction path. You should specify alternative isotopes for IRCMax jobs using the standard method. REQUIRED INPUT IRCMax requires two model chemistries as its options, separated IRCMax(model 2:model 1). Here is an example route section:

by a colon:

# IRCMax(B3LYP/6-31G(d,p):HF/6-31G(d,p))

This calculation will find the point on the HF/6-31G(d,p) reaction path where the B3LYP/6-31G(d,p) energy is at its maximum. The Zero will produce the data required for zero curvature transition state theoryoption (ZC-VTST) [169,170,173,174,175,176]. Consider the variational following route: # IRCMax(MP2/6-31G(d):HF/3-21G*,Zero,Stepsize=10)

This job will start from the HF/3-21G* TS and search along the HF/3-21G* IRC with a stepsize of 0.1 amu1/2 bohr until the maximum of the MP2/6-31G(d) energy (including the HF/3-21G* ZPE scaled by 0.91671) is bracketed. The position along the HF/3-21G* IRC for this MP2/6-31G(d) TS will then be optimized. The output includes all quantities required for the calculation of reaction rates using the ZC-VTST version of absolute rate theory: TS moments of inertia, all real vibrational frequencies (HF/3-21G*), the imaginary frequency for tunneling (fit to MP2/6-31G(d) + ZPE), and the total MP2/631G(d) + ZPE energy of the TS. ZC-VTST OPTIONS Zero

Include the zero-point energy in the IRCMax computation. PATH SELECTION OPTIONS Forward

Follow the path only in the forward direction. Reverse

Follow the path only in the reverse direction. ReadVector

Read in the vector to follow. The format is Z-matrix (FFF(I), I=1,NVAR), read as (8F10.6).


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MaxPoints= N

Number of points along the reaction path to examine (in each direction if both are being considered). The default is 6. StepSize= N 1/2

Step size along the reaction path, in units of 0.01 amu -Bohr. The default is 10. MaxCyc= N

Sets the maximum number of steps in each geometry optimization. The default is 20. Freq

Calculate the projected vibrational frequencies for motion perpendicular to the path, for each optimized point on the path [496]. This option is valid only for reaction paths in mass-weighted internal coordinates. COORDINATE SYSTEM SELECTION OPTIONS MassWeighted

Follow the path in mass-weighted internal (Z-matrix) coordinates (which is equivalent to following the path in mass-weighted Cartesian coordinates). MW is a synonym for MassWeighted . This is the default. Internal

Follow the path in internal (Z-matrix) coordinates without mass weighting. Cartesian

Follow the path in Cartesian coordinates without mass weighting. CONVERGENCE-RELATED OPTION VeryTight

Tightens the convergence criteria used in the optimization at each point along the path. This option is necessary if a very small step size along the path is requested.

CalcFC

Specifies that the force constants be computed at the first point CalcAll

Specifies that the force constants be computed at every point. FCCards

Reads the Cartesian forces and force constants from the input stream after the molecule specifications. This option can be used to read force constants recovered from the


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Quantum Chemistry Archive using its internal FCList command. The format for this

input is: Energy (format D24.16) Cartesian forces (lines of format 6F12.8) Force constants (lines of format 6F12.8)

The force constants are in lower triangular form: (( F ( J,I ) ,J=1 ,I ) ,I=1 ,NAt 3), where NAt3 is the number of Cartesian coordinates. If both FCCards and ReadIsotopes are specified, the masses of the atoms are input before the energy, Cartesian gradients and the Cartesian force constants. RESTART OPTION Restart

Restarts an IRC calculation which did not complete, or restarts an IRC calculation which did complete, but for which additional points along the path are desired.

Analytic gradients are required for the IRC portion of the calculation (model 1 above). Any non-compound energy method and basis set may be used for model 2.

IRC, Opt, Freq

LSDA This method keyword request a Local Spin Density Approximation calculation, using the Slater exchange functional and the VWN correlation functional for the DFT calculation. It is equivalent to SVWN. Note that LSDA is not uniquely defined in the literature. In fact, many differing but related methods are referred to using this term. Other programs offering an LSDA method may use somewhat different functionals. For example, some implement the functional specified by the SVWN5 keyword, while others use a correlation functional of Perdew. While Gaussian offers this keyword for convenience, it is probably better practice to specify the exact functional desired; see DFT Methods for full details on specifying and using Density Functional Methods in Gaussian.


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MaxDisk The MaxDisk keyword specifies the amount of disk storage available for scratch data, in 8-byte words. The value may optionally be followed by a units designation: KB, MB, GB, KW, MW or GB. Normally, this is set for a site in the site-wide Default.Route file. MP3, MP4, QCISD, CCSD, QCISD(T), and CCSD(T) calculations all now look at MaxDisk . If the calculation can be done using a full integral transformation while keeping disk usage under MaxDisk , this is done; if not, a partial transformation is done and some terms are computed in the AO basis. Since MP2 obeys MaxDisk as much as possible, the Stingy, NoStingy and VeryStingy options are not needed. Thus, it is crucial for a value for MaxDisk to be specified explicitly for these types of jobs, either within the route section or via a system wide setting in the Default.Route file. If MaxDisk is left unset, the program now assumes that disk is abundant and performs a full transformation by default (in contrast to Gaussian 94 where a partial transformation was the default in such cases). If MaxDisk is not set and sufficient disk space is not available for a full transformation, the job will fail. Not all calculations can dynamically control their disk usage, so the effects of this keyword vary: •

• •

•

•

•

•

SCF energy, gradient, and frequency calculations use a fixed amount of disk. This is quite small, only cubic in the size of the system) and is not usually a limitation. MP2 energies and gradients obey MaxDisk , which must be at least 2ON2. Analytic MP2 frequencies attempt to obey MaxDisk , but have minimum disk requirements. CI-Singles energies and gradients in the MO basis require about 4O2 N2 words of disk for a limited set of transformed integrals. Additional scratch space is required during the transformation and this is limited as specified by MaxDisk . This disk requirement can be eliminated entirely by performing a direct CI-Singles calculation by using CIS=Direct. CID, CISD, CCD, BD, and QCISD energies also have a fixed storage requirement 2 2 proportional to O N , with a large factor, but obey MaxDisk in avoiding larger storage requirements. CCSD, CCSD(T), QCISD(T), and BD(T) energies have fixed disk requirements proportional to ON3 which cannot be limited by MaxDisk . CID, CISD, CCD, QCISD densities and CCSD gradients have fixed disk requirements of about N4/2 for closed-shell and 3N4/4 for open-shell.

Click here for a detailed discussion of the efficient use of disk resources in Gaussian calculations.


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MINDO3 This method keyword requests a semi-empirical calculation using the MINDO3 Hamiltonian [43,44]. No basis set keyword should be specified.

Energies, "analytic" gradients, and numerical frequencies. Restricted open shell (RO) wavefunctions are limited to optimizations using the Fletcher-Powell and pseudo Newton-Raphson methods (the FP and EnOnly options to Opt, respectively).

The MINDO3 energy appears in the output file as follows (followed by the x, y, and z components of the dipole moment): Energy= -.080309984532 NIter= 10. Dipole moment= .000000 .000000 -.739540


Molecular Mechanics Methods There are three molecular mechanics methods available in Gaussian. They were implemented for use in ONIOM calculations, but they are also available as independent methods. No basis set keyword should be specified with these keywords. The following force fields are available: AMBER : The AMBER force field as described in [37]. The actual parameters



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by the user in the input stream for the current job (or a previous job when reading parameters from the checkpoint file). By default, when no relevant option is given, the hard-wired parameters are the only ones used. HardFirst

Read additional input stream, with hard-wired parameters having priority over theparameters read-in, softfrom ones.theHence, read-in parameters are used only if there is no corresponding hard-wired value. Note that wildcards matches within the hardwared parameter set take precidence over soft parameters, even when the latter contains an exact match for the same item. Use SoftFirst if you want to override hard-wired parameter matches. SoftFirst



Read parameters from the checkpoint file. Any non-standard (soft) parameters present in the checkpoint file are used with higher priority than corresponding hard-wired parameters, unless HardFirst is also specified.


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NewParameters





found. LastEquiv



Specifies an SP3 aliphatic carbon atom. Specifies an SP3 aliphatic carbon atom with a partial charge of 0.32. O-O--0.5 Specifies a carbonyl group oxygen atom with a partial charge of -0.5.



ONIOM, Geom=Connect


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Unless otherwise indicated, distances are in Angstroms, angles are in degrees, energies are in Kcal/mol and charges are in atomic units. Function equivalencies to those found in standard force fields are indicated in parentheses. In equations, R refers to distances and θ refers to angles. Wildcards may be used in any function definition. They are indicated by a 0 or an asterisk. In MM force fields, the non-bonded (Vanderwaals and electrostatic) interactions are evaluated for every possible pair of atoms. However, interactions between pairs of atoms that are separated by three bonds or less are usually scaled down (in most force fields, using a factor 0.0 for pairs separated by one or two bonds, and some value between 0.0 and 1.0 for pairs that are separated by three bonds). There are a number of ways to implement the calculation of non-bonded interactions. We follow a two-step procedure. First, we calculate the interactions between all pairs, without taking the scaling into account. In this step, we can use computationally efficient (linear scaling) algorithms. In the second step, we subtract out the contributions that should have been scaled, but were included in the first step. Since this involves only pairs that are close to each other based on the connectivity, the computer time for this step scales again linearly with the size of the system. Although at first sight it seems that too much work is done, the overall algorithm is the more efficient than the alternatives. In the soft force field input, the NBDir function entry corresponds to the calculation of all the pairs, and theto NBTerm entryeasier, is usedyou for can the subsequent of themaster individual pairs. However, make things specify just subtraction the non-bonded function NonBon, which is automatically expanded into the actual functions NBDir and NBTerm during pre-processing. Vanderwaals parameters, used for NBDir and NBTerm (See MMFF94 below for MMFF94-type Vanderwaals parameters). VDW Bond-length Well-depth


Atomic-pol Atomic polarizability (Angstrom3). NE Slater-Kirkwood effective number of valence electrons (dimensionless). Scale1 Scale factor (Angstrom1/4).


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Scale2 Scale factor (dimensionless). DFlag 1.0 for donor type atom, 2.0 for acceptor type, otherwise 0.0.




01 2 3 4

No Vanderwaals Arithmetic (as for Dreiding) Geometric (as for UFF) Arithmetic (as for Amber) MMFF94-type Vanderwaals C-Type is the Coulomb type: 0 No Coulomb 1 1/R 2 1/R 2 3 1/R buffered (MMFF94) V-Cutoff and C-Cutoff are the Vanderwaals and Coulomb cutoffs (respectively): 0>0 No cutoff Hard cutoff <0 Soft cutoff VScale1-3 are Vanderwaals scale factors for 1 to 3 bond separated pairs. CScale1-3 are





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Step down table Table Original-atom-type Stepping-down-type(s).





Harmonic stretch III (UFF [1a]): k *(R-R ij)2 Equilibrium bond length R ij = (1 - PropC *ln BO)*(R i + R j) + R en Force constant: k = 664.12*Zi*Z j/(R ij3) Electronegativity correction: R i*R j*[Sqrt(Xi) - Sqrt(X j)]2/(Xi*R i + X j*R j)


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HrmStr3 Atom-type1 Atom-type2 BO PropC

BO Bond order (if <0, it is determined on-the-fly) PropC Proportionality constant i j R and Rdefined are atomic bond radii with . X i atomic and X j are GMPdefined electronegativity values with EleNeg . Z i defined and Z j are theAtRad effective charges with

EffChg.


ForceC Force constant Req Equilibrium bond length DLim

Dissociation limit






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UFF 3-term bend (UFF [11]): 2

k*(C0 + C1*cos(θ))+C2*cos(2θ) where C2=1/(4 * sin(θeq )), C1 = -4*C2*cos(θ eq) and C0=C2*(2*cos(θ eq2)+1) Force constant: k = 664.12*Zi*Zk *(3*R ij*R jk *(1-cos(θeq2))-cos(θeq)*R ik 2)/R ik 5 UFFBnd3 Atom-type1 Atom-type2 Atom-type3 θeq BO12 BO23 PropC

θeq

Equilibrium angle BO12 Bond order for Atom-type1–Atom-type2 (when <0, it is determined on-the-fly) BO23 Bond order for Atom-type2–Atom-type3 (when <0, it is determined on-the-fly) PropC Proportionality constant i R j AtRad X i, X j and X k are GMP R , and Rk are atomic defined with electronegativity definedbond withradii EleNeg . Z , Z and Z are.effective atomic charges defined i

j

k

with EffChg. UFF 2-term bend (UFF [10]): [k/( Per 2)]*[1-cos( Per *θ)] 2 2 5 Force constant: k = 664.12*Zi*Zk *(3*R j*R i jk *(1-cos( Per ))-cos( Per )*R ik )/R ik






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MMFF94 Linear Bend (MMFF94 [4]): ForceC *(1+cos(θ)) LinBnd2 Atom-type1 Atom-type2 Atom-type3 ForceC ForceC Force constant (md)


Mag 4 NPaths PO1-PO4 Phase offsets Mag 1...Mag 4 V/2 magnitudes NPaths Number of paths (if < 0, determined on-the-fly).

Dreiding torsion (Dreiding [13]): V *[1-cos( Period *(θ- PO))]/(2* NPaths) DreiTrs Atom-type1 Atom-type2 Atom-type3 Atom-type4 V PO Period NPaths

V Barrier height V PO Phase offset Period Periodicity NPaths Number of paths (if < 0, determined on-the-fly).



UFF torsion with bond order based barrier height (UFF [17]):


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[V/2]*[1-cos( Period * PO)* cos( Period *θ)]/ NPaths where V = 5*Sqrt(U j*Uk )*[1+4.18*Log( BO12)] UFFTorB Atom-type1 Atom-type2 Atom-type3 Atom-type4 Period PO BO12 NPaths







•

•



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Substructures may be used to define different parameter values for a function for distinct ranges of some geometrical characteristic. Substructure numbers are appended to the function name, separated by a hyphen (e.g., HrmStr-1, HrmStr-2 and so on). The following substructures apply to functions related to bond stretches: •

-1

Single bond: 0.00 ≤ bond order < 1.50


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• •

-2 -3

Double bond: 1.50 ≤bond order < 2.50 Triple bond: bond order ≥ 2.50


-1 -2 -3

0 ≤ θ ≤ 45 45 < θ ≤ 135 135 < θ ≤ 180


-i-n


For dihedral angles, one or two substructures may be used (e.g., AmbTrs-1-2). Use a zero for the first substructure to specify only the second substructure. First substructure : • • • •

-0 -1 -2 -3

Skip this substructure (substructure "wildcard") Single central bond: 0.00 ≤ bond order < 1.50 Double central bond: 1.50 ≤ bond order < 2.50 Triple central bond: bond order ≥ 2.50

Second substructure: • • •

--ii-1 -2 -i-3

order ≤ 1.70) Resonance central (1.30over ≤ bond Amide central bondbond (priority resonance) None of the above


H_ C_2 C_2 * * *

C_2 360.0 1.08 C_2 350.0 1.50 C_2 500.0 1.40 C_2 * 50.0 120.0 C_2 C_2 * 5.0 180.0 C_2 C_2 * 45.0 180.0

2.0 -1.0 2.0 -1.0

MNDO


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This method keyword requests a semi-empirical calculation using the MNDO Hamiltonian [43,45,46,47,48,49,50,51,52,54]. No basis set keyword should be specified.

Energies, "analytic" gradients, and numerical frequencies. Restricted open shell (RO) wavefunctions are limited to optimizations using the Fletcher-Powell and pseudo Newton-Raphson methods (FP and EnOnly, respectively).

The MNDO energy appears in the output file as follows (followed by the x, y, and z components of the dipole moment): Energy= -.0908412558735 NIter= 10. Dipole moment= .000000 .000000 -.739540


MP2 MP3 MP4 MP5 These method keywords request a Hartree-Fock calculation (RHF for singlets, UHF for higher multiplicities) followed by a Møller-Plesset correlation energy correction [60], truncated at second-order for MP2 [21,22,23,25,65], third order for MP3 [61,66], fourthorder for MP4 [62], and fifth-order for MP5 [64]. Analytic gradients are available for MP2 [22,23,139,140], MP3 and MP4(SDQ) [141,142], and analytic frequencies are available for MP2 [25]. AVAILABLE ALGORITHMS FOR MP2

There are four basic algorithms for MP2 calculations and for producing transformed (MO) integrals on disk:


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•

Semi-Direct , which uses both main memory and external (disk) storage as

available [23]. This is the default algorithm. •

Direct , which uses no external storage by recomputing the integrals as needed

during the •

•

transformation. Conventional , which stores the transformed integrals on disk. This was the only method in Gaussian the only method integrals on available disk in Gaussian 90. It88is, and seldom a good choicefor ongenerating any but theMO smallest computer systems. In-core, in which all the AO integrals are generated and stored in main memory, then used without storing them externally.

The default is to decide between the in-core, direct, and semi-direct algorithms based on available memory and disk. The available disk can be specified via the MaxDisk keyword, either in the route section or (preferably) in the Default.Route file. Note that selection of the direct or semi-direct MP2 and transformation algorithms is 03). separate from selecting direct SCF (which the defaultintegrals SCF algorithm in Gaussian The E(2) calculation or transformation then is recomputes as needed in the form required for vectorization. VARIATIONS OF MP4 MP4(DQ) is specified to use only the space of double and quadruple substitutions, MP4(SDQ) for single, double and quadruple substitutions, or MP4(SDTQ) for full MP4 with single, double, triple and quadruple substitutions [62,63]. Just specifying MP4 defaults to MP4(SDTQ).

LIMITATIONS FOR MP5

The MP5 code has been written for the open shell case only, and so specifying MP5 defaults to a UMP5 calculation. This method requires O3V3 disk storage and scales as O4V4 in cpu time. FROZEN-CORE OPTIONS (POST-SCF METHODS) FC

The frozen-core options for defining inner-shells to be excluded from the correlation calculation are valid with these keywords. See the discussion here for details. ALGORITHM SELECTION OPTIONS (MP2 METHODS)

Note: The appropriate algorithm for MP2 will be selected automatically based on the settings of %Mem and MaxDisk . Thus, these options are almost never needed. FullDirect

Forces the "fully direct" algorithm, which requires no external storage beyond that for the


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SCF. Requires a minimum of 2OVN words of main memory (O=number of occupied orbitals, V =number of virtual orbitals, N =number of basis functions). This is seldom a good choice, except for machines with very large main memory and limited disk. SemiDirect

Forces the semi-direct algorithm. Direct

Requests some sort of direct algorithm. The choice between in-core, fully direct and semidirect is made by the program based on memory and disk limits and the dimensions of the problem. InCore

Forces the in-memory algorithm. This is very fast when it can be used, but requires N4/4 words of memory. It is normally used in conjunction with SCF=InCore. NoInCore prevents the use of the in-core algorithm.

MP2: Energies, analytic gradients, and analytic frequencies. ROMP2 is available for

energies only. MP3, MP4(DQ) and MP4(SDQ): Energies, analytic gradients, and numerical

frequencies. MP4(SDTQ) and MP5: Analytic energies, numerical gradients, and numerical

frequencies.

HF, SCF, Transformation , MaxDisk

Energies. The MP2 energy appears in the output as follows, labeled as EUMP2: E2=

-.3906492545D-01 EUMP2=

-.75003727493390D+02

Energies for higher-order Møller-Plesset methods follow. Here is the output from an MP4(SDTQ) calculation: Time for triples= .04 seconds. MP4(T)= -.55601167D-04 E3= -.10847902D-01 EUMP3= E4(DQ)= -.32068082D-02 UMP4(DQ)= E4(SDQ)= -.33238377D-02 UMP4(SDQ)=


-.75014575395D+02 -.75017782203D+02 -.75017899233D+02

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E4(SDTQ)=

-.33794389D-02

UMP4(SDTQ)=

-.75017954834D+02

The energy labelled EUMP3 is the MP3 energy, and the various MP4-level corrections appear after it, with the MP4(SDTQ) output coming in the final line (labeled UMP4(SDTQ)).

Name This keyword specifies the username that is stored in the archive entry for the calculation. It takes the desired username as its parameter (e.g., Name=RChavez). This keyword is of most use to Gaussian users who also use the Browse Quantum Chemistry Database System. On of UNIX systems, the default login name the user who runs the job.for the user name is the operating system-level

Archive, Test, Rearchive

NMR This properties keyword predicts NMR shielding tensors and magnetic susceptibilities using the Hartree-Fock method, all DFT methods and the MP2 method [232,234,528]. NMR shielding tensors may be computed with the Continuous Set of Gauge Transformations (CSGT) method [231,233,235] and the Gauge-Independent Atomic Orbital (GIAO) method [226,227,228,229,230]. Magnetic susceptibilities may also be computed with both GIAOs [236,237] and CGST. Gaussian also supports the IGAIM method [231,233] (a slight variation on the CSGT method) and the Single Origin method, for both shielding tensor and magnetic susceptibilities. Structures used for NMR calculations should have been optimized at a good level of theory. Note that CSGT calculations require large basis sets to achieve accurate results. Spin-spin coupling constants may also be computed during an NMR job [238,239,240,241], via the SpinSpin option.


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SpinSpin

Compute spin-spin coupling constants in addition to the usual NMR properties. This calculation type has a computational cost of about twice that of computing vibrational frequencies. It is available only for Hartree-Fock and DFT methods. CSGT

Compute NMR properties using the CSGT method only. GIAO

Compute NMR properties using the GIAO method only. This is the default. IGAIM

Use atomic centers as gauge origins. SingleOrigin

Use a single gauge origin. This method is provided for comparison purposes but is not generally recommended. All

Compute properties with all three of the SingleOrigin , IGAIM, and CSGT methods. PrintEigenvectors

Display the eigenvectors of the shielding tensor for each atom

SCF, DFT and MP2 methods. In Gaussian 03, NMR may be combined with SCRF.

Here is an example of the default output from NMR : Magnetic properties (GIAO method) Magnetic shielding (ppm): 1 C Isotropic = 57.7345 XX= 48.4143 YX= .0000 XY= .0000 YY= -62.5514 XZ= .0000 YZ= .0000 2 H Isotropic = 23.9397 XX= 27.3287 YX= .0000 XY= .0000 YY= 24.0670 XZ= .0000 YZ= .0000

Anisotropy = 194.4092 ZX= .0000 ZY= .0000 ZZ= 187.3406 Anisotropy = 5.2745 ZX= .0000 ZY= .0000 ZZ= 20.4233

For this molecular system, the values for all of the atoms of a given type are equal, so we have truncated the output after the first two atoms.


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The additional output from spin-spin coupling computations appears as follows: Total nuclear spin-spin coupling K (Hz): 1 2 1 0.000000D+00 2 0.147308D+02 0.000000D+00 Total nuclear spin-spin coupling J (Hz): 1 2 1 0.000000D+00 2 0.432614D+03 0.000000D+00

The various components of the coupling constants precede this section in the output file. It displays the matrix of isotropic spin-spin coupling between pairs of atoms in lower triangular form. The K matrix gives the values which are isotope-independant, and the J matrix gives the values taking the job's specific isotopes into account (whether explicitly specifed or the default isotopes).

ONIOM This keyword requests a two- or three-layer ONIOM [153,154,155,156,157,158,159]. In this procedure, the molecular system being studied is divided into two or three layers which are treated with different model chemistries. The results are then automatically combined into the final predicted results. The layers are conventionally known as the Low, Medium and High layers. By default, atoms are placed into the High layer. (From a certain point of view, any conventional calculation can be viewed as a one-layer ONIOM.) Layer assignments are specified as part of the molecule specification (see below). For ONIOM(MO:MM) jobs, the ONIOM optimization procedure is enhanced in Gaussian 03 to use microiterations [163] and an optional quadratic coupled algorithm [162]. The latter takes into account the coupling between atoms using internal coordinates (typically, those in the model system) and those in Cartesian coordinates (typically, the atoms only in the MM layer) in order to produce more accurate steps (the latter can be requested with Opt=QuadMacro). ONIOM(MO:MM) calculations can take advantage of electronic embedding. Electronic embedding incorporates the partial charges of the MM region into the quantum mechanical Hamiltonian. This technique provides a better description of the electrostatic interaction between the QM and MM regions and allows the QM wavefunction to be polarized. REQUIRED INPUT


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The two or three desired model chemistries are specified as the options to the ONIOM keyword, in the order High, Medium, Low (the final one may obviously be omitted). The distinct models are separated by colons. For example, this route section specifies a threelayer ONIOM calculation, using UFF for the Low layer, AM1 for the Medium layer, and HF for the High layer: # ONIOM(HF/6-31G(d):AM1:UFF)

Atom layer assignment is done as part of the molecule specification, via additional parameters on each line according to the following syntax: atom coordinate-spec layer [link-atom [bonded-to [ scale-fac1 [ scale-fac2 [ scale-fac3]]]]]

where atom and coordinate-spec represent the normal molecule specification input for the atom. Layer is a keyword indicating the layer assignment for the atom, one of High, Medium and Low. The other optional parameters specify how the atoms located at a link-atom layer boundary are atom to be (it treated. You use to partial specifycharge the atom which to replace the current can include atom type and andwith other parameters). Link atoms are necessary when covalent bonding exists between atoms in different layers in order to saturate the (otherwise) dangling bonds. Note: All link atoms must be specified by the user. Gaussian 03 does not define them

automatically or provide any defaults. The bonded-to parameter specifies which atom the current atom is to be bonded to during the higher-level calculation portion. If it is omitted, Gaussian will attempt to identify it automatically. In general, Gaussian 03 determines bond distances between atoms and their link atoms by scaling the original bond distance (i.e., in the real system), using scaling factors which the program determines automatically. However, you can also specify these scale factors explicitly. For a two-layer calculation, the scale factors specify the link atom bond distance in the model system when calculated at the low and high levels (respectively). For a three-layer ONIOM, up to three scale factors may be specified (in the order low, medium, high). All of these scale factors correspond to the g-factor parameter as defined in reference [158], extended to allow separate values for each ONIOM calculation level. For a two-layer ONIOM, if only one parameter is specified, then both scale factors will use that value.will Foruse a three-layer if only one parameter is specified, allscale three scale factors that value; ONIOM, if only two parameters are specified, then thethen third factor will use the second value. If a scale parameter is explicitly set to 0.0, then the program will determine the corresponding scale factor in the normal way. Thus, if you want to change only the second scale factor (model system calculated at the medium level), then you must explicitly set the first scale factor to 0.0. In this case, for a three-layer ONIOM, the third scale factor will have the same value as the second parameter unless it is explicitly


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assigned a non-zero value (i.e., in this second context, 0.0 has the same meaning as an omitted value). PER-LAYER CHARGE AND SPIN MULTIPLICITY

Multiple charge spin multiplicity pairsthe may also be ONIOM calculations. Forand two-layer ONIOM jobs, format forspecified this inputfor line is: chrg real-low spinreal-low [chrg model-high spinmodel-high [chrg model-low spinmodel-low [chrg real-high spinreal-high]]]

where the subscript indicates the calculation for which the values will be used. The fourth pair applies only to ONIOM=SValue calculations. When only a single value pair is specified, all levels will use those values. If two pairs of values are included, then the third pair defaults to the same values as in the second pair. If the final pair is omitted for an S-value job, it defaults to the values for the real system at the low level. Values and defaults ONIOM follow an analogous pattern the subscripts below,for thethree-layer first character is onecalculations of: Real , Int =Intermediate system, and (in Mod =Model system, and the second character is one of: H , M and L for the High, Medium and Low levels): c RealL s RealL [c IntM s IntM [c IntL s IntL [cModH sModH [cModM sModM [cModL sModL]]]]]

For 3-layer ONIOM=SValue calculations, up to three additional pairs may be specified: ... c IntH s IntH [c RealM s RealM [c RealH s RealH ]] Defaults forlevel missing charge/spin multiplicity pairsonly are ataken from thesix next calculation and/or system size. Thus, when subset of the orhighest nine pairs are specified, the charge and spin multiplicity items default according to the following scheme, where the number in each cell indicates which pair of values applies for that calculation in the corresponding :circumstances: Real-Low

1 2 3 4 1 1 1 1

5 1

6 1

only) 7 8 1 1

Int-Med Int-Low Model-High Model-Med Model-Low Int-High Real-Med Real-High

11 1 1 1 1 1 1

23 4 5 5 2 1 1

23 4 5 6 2 1 1

23 4 5 6 7 1 1

Calculation

Charge & Spin Defaults # Pairs Specified (SValue

22 2 2 2 2 1 1

23 2 2 2 2 1 1

23 4 4 4 2 1 1


23 4 5 6 7 8 8

9 1 23 4 5 6 7 8 9

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EmbedCharge

Use MM charges from the real system in the QM calculations on the model system(s). NoEmbedCharge is the default. MK

Specifies that Merz-Kollman-Singh (see Population ) approximate charges be used during geometry optimization microiterations with electronic embedding. It is the default. ScaleCharge=ijklmn

Specifies scaling parameters for MM charges during electronic embedding in the QM calculations. The integers are multiplied by 0.2 to obtain the actual scale factors. Atoms bonded to the inner layers use a scale factor of 0.2n, those two bonds away use 0.2m, and so on. However, the values of i through n must be monotonically decreasing, and the largest value among them is used for all parameters to its left. Thus, 555500, 123500 and 500 are all equivalent. The default value is 500 (i.e., 555500). ScaleCharge implies EmbedCharge. SValue

Requests that the full square be done for testing, to produce substituent values ( S-values) for the S-value test [160]. Additional charge and spin multiplicity pair(s) may be specified for the additional calculations (see below). Compress

Compress operations and storage to active atoms during ONIOM second derivative calculations; this is the default. NoCompress performs the calculation without compression. Blank does the uncompressed calculation but then discards contributions from inactive atoms (which are currently non-zero only for nuclear moment perturbations: shielding and spin-spin coupling tensors).

Energies, gradients and frequencies. Note that if any of the specified models require numerical frequencies, then numerical frequencies will be computed for all models, even when analytic frequencies are available. ONIOM can also perform CIS and TD calculations for one or more layers. The Gen, Pseudo=Read, ChkBas, Sparse and NoFMM keywords may also be specified for relevant models. Density fitting sets may also be used when applicable, and they are specified in the usual manner (see the examples). NMR calculations may be performed with the ONIOM model.


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Geom=Connect, Molecular Mechanics keywords, Opt=QuadMacro

Molecule Specifications for ONIOM Jobs. Here is a simple ONIOM input

file:

# ONIOM(B3LYP/6-31G(d,p):AM1:UFF) Opt Test 3-layer ONIOM optimization 0 1 C O,1,B1 H,1,B2,2,A1 C,1,B3,2,A2,3,180.0,0

M H

C,4,B4,1,A3,2,180.0,0 H,4,B5,1,A4,5,D1,0 H,4,B5,1,A4,5,-D1,0 H,5,B6,4,A5,1,180.0,0 H,5,B7,4,A6,8,D2,0 H,5,B7,4,A6,8,-D2,0

L H M M L L L

variable definitions

The High layer consists of the first three atoms (placed there by default). The other atoms are explicitly placed into the Medium and Low layers. Note that the Z-matrix specification must include the final 0 code indicating the Z-matrix format when ONIOM input is included. Here is an input file for a two-layer ONIOM calculation using a DFT method for the high layer and Amber for the low layer. The molecule specification includes atom types (which are optional with UFF but required by Amber). Note that atom types are used for both the main atom specifications and the link atoms: # ONIOM(B3LYP/6-31G(d):Amber) Geom=Connectivity 2 layer ONIOM job

Charge/spin for entire molecule (real system), model system-high level &

0 1 0 1 0 1

model-l ow C-CA--0.25 C-CA--0.25 C-CA--0.25 C-CA--0.25 C-CA--0.25 C-CA--0.25 H-HA-0.1 H-HA-0.1 H-HA-0.1 C-CA--0.25

0 0 0 0 0 0 0 0 0 0

-4.703834 -3.331033 -2.609095 -3.326965 -4.748381 -5.419886 -0.640022 -5.264565 -2.766244 -1.187368

-1.841116 -1.841116 -0.615995 0.607871 0.578498 -0.619477 -1.540960 -2.787462 -2.785438 -0.586452


-0.779093 L -0.779093 L H-HA-0.1 3 -0.779093 H -0.778723 H -0.778569 H -0.778859 L H-HC-0.1 5 -0.779336 L -0.779173 L -0.779321 L -0.779356 L H-HA-0.1 3

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C-CA--0.25 H-HA-0.1 H-HA-0.1 C-CA--0.25 C-CA--0.25 H-HA-0.1 H-HA-0.1 H-HA-0.1

0 0 0 0 0 0 0 0

-2.604215 -5.295622 -6.519523 -1.231354 -0.515342 -3.168671 -0.670662 0.584286

1.832597 1.532954 -0.645844 1.832665 0.610773 2.777138 2.778996 0.637238

-0.778608 -0.778487 -0.778757 -0.778881 -0.779340 -0.778348 -0.779059 -0.779522

H L H-HA-0.1 L L H-HC-0.1 L L H-HA-0.1 L L

5 11 11

1 2 1.5 6 1.5 8 1.0 2 3 1.5 9 1.0 3 4 1.5 10 1.5 4 5 1.5 11 1.5 5 6 1.5 12 1.0 6 13 1.0 7 10 1.0 8 9 10 15 1.5 11 14 1.5 16 1.0 12 13 14 15 1.5 17 1.0 15 18 1.0 16 17 18

This input file was created by GaussView. Note that it contains connectivity information for use with Geom=Connect. This job also illustrates the use of multiple charge and spin multiplicity values for ONIOM jobs. This example should be used for illustrative purposes only. We thank Prof. K Nishimoto for pointing out several scientific problems with running this calculation. A Complex ONIOM Route. Here is an example of a complex ONIOM route section: # ONIOM(BLYP/6-31G(d)/Auto TD=(NStates=8):UFF)

This example uses density fitting for the DFT high layer time-dependent excited states calculation. Freezing Atoms During ONIOM Optimizations. ONIOM optimizations can take

advantage of the optional second field within molecule specifications. This field defaults to 0 if omitted. If it is set to -1, then the corresponding atom is frozen during geometry optimizations: C -1 0.0 0.0 0.0 H 0 0.0 0.0 0.9 ...


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Note that the atom will also be frozen during non-ONIOM optimizations provided that they are performed in coordinates other than redundant internal coordinates. For the latter, which are the default, use the Opt=ModRedundant option to freeze atoms. For ONIOM jobs only, if the field is set to a negative value other than -1, it is treated as part a rigid during the optimization: all atoms with the same value (< -1) moveofonly as afragment rigid block. S-Value Test. Here is some output from the ONIOM=SValue option: S-Values (between gridpoints) and energies: high med low

4 -39.322207 7 -39.305712 9 -114.479426 -153.801632 -193.107344 2 -39.118688 5 -39.106289 8 -114.041481 -153.160170 -192.266459 1 -38.588420 3 -38.577651 6 -112.341899 -150.930320 -189.507971 model mid real

The integers are the gridpoints, and under each one is the energy value. Horizontally between the grid points are the S-values. These are the s-values obtained with the absolute energies. However, be aware than when applying the S-value test, relative energies and S-values need to be used (see reference [160]).

Opt

This keyword requests that a geometry optimization be performed. The geometry will be adjusted until a stationary point on the potential surface is found. Gradients will be used if available. For the Hartree-Fock, CIS, MP2, MP3, MP4(SDQ), CID, CISD, CCD, CCSD, QCISD, CASSCF, and all DFT and semi-empirical methods, the default algorithm for both minimizations (optimizations to a local minimum) and optimizations to transition states and higher-order saddle points is the Berny algorithm using redundant internal coordinates [149,15] (specified by the Redundant option). The default algorithm for all methods lacking analytic gradients is the eigenvalue-following algorithm (Opt=EF). The Berny algorithm using internal coordinates (Opt=Z-matrix) is also available [136,148,529]. The remainder of this quite lengthy section discusses various aspects of geometry optimizations, and it includes these subsections: • • •

Options to the Opt keyword. Overview of geometry optimizations in Gaussian 03. Ways of generating initial force constants.


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• • •

•

Optimizing to transition states and higher-order saddle points. Summary of the Berny optimization algorithm. Notes on optimizing in redundant internal coordinates, including examples of Opt input and output and using the ModRedundant option. Examples for Opt=Z-matrix.

Users should consult those subsection(s) that apply to their interests and needs. Basic information as well as techniques and pitfalls related to geometry optimizations are discussed in detail in chapter 3 of Exploring Chemistry with Electronic Structure Methods [308]. See also Appendix B if you are interested in details about setting up Zmatrices for various types of molecules. GENERAL PROCEDURAL OPTIONS MaxCycle= N

Sets the maximum number of optimization to N . The default maximum of 20 and twice the number of redundant internal steps coordinates in use (for is thethe default procedure) or twice the number of variables to be optimized (for other procedures). MaxStep= N

Sets the maximum size for an optimization step (the initial trust radius) to 0.01 N Bohr or radians. The default value for N is 30. TS

Requests optimization to a transition state rather than a local minimum. Saddle= N

Requests optimization to a saddle point of order N . QST2

Search for a transition structure using the STQN method. This option requires the reactant and product structures as input, specified in two consecutive groups of title and molecule specification sections. Note that the atoms must be specified in the same order in the two structures. TS should not be specified with QST2. QST3

Search for a transition structure using the STQN method. This option requires the reactant, product, andspecification initial TS structures input, in three consecutive of title and molecule sections.asNote thatspecified the atoms must be specified groups in the same order within the three structures. TS should not be specified with QST3. Path=M

In combination with either the QST2 or the QST3 option, requests the simultaneous optimization of a transition state and an M -point reaction path in redundant internal coordinates [164]. No coordinate may be frozen during this type of calculation.


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If QST2 is specified, the title and molecule specification sections for both reactant and product structures are required as input as usual. The remaining M -2 points on the path are then generated by linear interpolation between the reactant and product input structures. The highest energy structure becomes the initial guess for the transition structure. At each step in the path relaxation, the highest point at each step is optimized toward the transition structure. If QST3 is specified, a third set of title and molecule specification sections must be included in the input as a guess for the transition state as usual. The remaining M -3 points on the path are generated by two successive linear interpolations, first between the reactant and transition structure and then between the transition structure and product. By default, the central point is optimized to the transition structure, regardless of the ordering of the energies. In this case, M must be an odd number so that the points on the path may be distributed evenly between the two sides of the transition structure. In the output for a simultaneous optimization calculation, the predicted geometry for the optimized transition structure is followed by a list of all M converged reaction path structures. The treatment of the input reactant and product structures is controlled by other options: OptReactant, OptProduct, BiMolecular. Note that the SCF wavefunction for structures in the reactant valley may be quite different from that of structures in the product valley. Guess=Always can be used to prevent the wavefunction of a reactant-like structure from being used as a guess for the wavefunction of a product-like structure. OptReactant Specifies that the input structure for

the reactant in a simultaneous optimization calculation should be optimized to a local minimum. This is the default. NoOptReactant retains the input structure as a point that is already on the reaction path (which generally means that it should have been previously optimized to a minimum). OptReactant may not be combined with BiMolecular . BiMolecular

Specifies that the reactants or products are bimolecular and that the input structure will be used as an anchor point. This anchor point will not appear as one of the M points on the path. Instead, it will be used instead to control how far the reactant side spreads out from the transition state. By default, this option is off. OptProduct

Specifies that the input structure for the product in a simultaneous optimization calculation should be optimized to a local minimum. This is the default. NoOptProduct retains the input structure as a point that is already on the reaction path (which generally means that it should have been previously optimized to a minimum). Optproduct may not be combined with BiMolecular .


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Conical

Search for a conical intersection or avoided crossing using the state-averaged CASSCF method. See the discussion of the CASSCF keyword for details and examples. Avoided is a synonym for Conical. Note that CASSCF=SlaterDet is needed in order to locate a conical intersection between a singlet state and a triplet state. Restart

Restarts a geometry optimization from the checkpoint file. In this case, the entire route section will consist of the Opt keyword and the same options to it as specified for the original job (along with Restart). No other input is needed (see the examples). NoFreeze

Activates (unfreezes) all variables (normally used with Geom=Check ). ModRedundant

Add, delete or modify redundant internal coordinate definitions (including scan and constraint specification. information). When This option a separate following the geometry used inrequires conjunction with input or QST3 ,a QST2section ModRedundant input section must follow each geometry specification. AddRedundant is synonymous with ModRedundant. Lines in a ModRedundant input section use the following syntax: [Type] N1 [ N2 [ N3 [ N4]]] [[+=]value] [A | F] [[min] max]] [Type] N1 [ N2 [ N3 [ N4]]] [[+=]value] B [[min] max]] [Type] N1 [ N2 [ N3 [ N4]]] K | R [[min] max]] [Type] N1 [ N2 [ N3 [ N4]]] [[+=]value] D [[min] max]] [Type] N1 [ N2 [ N3 [ N4]]] [[+=]value] H diag-elem [[min] max]] [Type] N1 [ N2 [ N3 [ N4]]] [[+=]value] S nsteps stepsize [[min] max]] N 1, N 2, N 3 and N 4 are atom numbers or wildcards (discussed below). Atom numbering begins at 1, and any dummy atoms are not counted. Value specifies a new value for the specified coordinate, and +=value increments the coordinate by value.

The atom numbers and coordinate value are followed by a one-character code letter indicating the coordinate modification to be performed; the action code is sometimes followed by additional required parameters as indicated above. If no action code is included, the default action is to add the specified coordinate. These are the available action codes: •

A

Activate the coordinate for optimization if it has been frozen.


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• • •

•

•

•

•

Freeze the coordinate in the optimization. Add the coordinate and build all related coordinates. Remove the coordinate and kill all related coordinates containing this coordinate. R Remove the coordinate from the definition list (but not the related F B K

coordinates). D Calculate numerical second derivatives for the row and column of the initial Hessian for this coordinate. H Change the diagonal element for this coordinate in the initial Hessian to diag-elem. Perform a relaxed potential energy surface scan. Set the initial value of this S coordinate to value (or its current value), and increment the coordinate by stepsize a total of nsteps times, performing an optimization from each resulting starting geometry.

An asterisk (*) in the place of an atom number indicates a wildcard. Min and max then define a range (or maximum valuespecified if min isby notthe given) coordinate containing wildcards. The action actionforcode is takenspecifications only if the value of the coordinate is in the range. Here are some examples of wildcard use: • • • • • • •

* All atoms specified by Cartesian coordinates ** All defined bonds All defined bonds with atom 3 3* * * * All defined valence angles * 4 * All defined valence angles around atom 4 * ** 3* 4* *

All defined dihedral angles around the bond connecting atoms 3 and 4

When the action codes K and B are used with one or two atoms, the meaning of a wildcard is extended to include all applicable atoms, not just those involving defined coordinates. By default, the coordinate type is determined from the number of atoms specified: Cartesian coordinates for 1 atom, bond stretch for 2 atoms, valence angle for 3 atoms and dihedral angle for 4 atoms. Optionally, Type can be used to designate these and additional coordinate types: •

• • • •

Cartesian coordinates. In this case, value, min and max are interpreted as the X, Y and Z coordinates (respectively). B Bond length A Valence angle D Dihedral angle L Linear bend specified by three atoms (or if N 4 is -1) or by four atoms, where the fourth atom is used to determine the 2 orthogonal directions of the linear bend. X


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•

In this case, value, min and max are each pairs of numbers, specifying the two orthogonal bending components. O Out-of-plane bending coordinate for a center ( N 1) and three connected atoms.

See the examples later in this section for illustrations of the use of this keyword. InitialHarmonic= N

Add harmonic constraints to the initial structure with force constant N /1000 Hartree/Bohr 2. IHarmonic is a synonym for this option. ChkHarmonic= N

Add harmonic constraints to the initial structure saved on the chk file with force constant N /1000 Hartree/Bohr 2. CHarmonic is a synonym for this option. ReadHarmonic= N 2 Add harmonic constraints a structure read in the inputisstream (in theforinput with force constant N /1000toHartree/Bohr . RHarmonic a synonym this orientation), option.

COORDINATE SYSTEM SELECTION OPTIONS Redundant

Perform the optimization using the Berny algorithm in redundant internal coordinates. This is the default for methods for which analytic gradients are available. Z-matrix

Perform the optimization in internal coordinates. In this case, the keyword FOpt rather Opt requests that the program verify that a full optimization is being done (i.e., that than the variables including inactive variables are linearly independent and span the degrees of freedom allowed by the molecular symmetry). The POpt form requests a partial optimization in internal coordinates. It also suppresses the frequency analysis at the end of optimizations which include second derivatives at every point (via the CalcAll option). Cartesian

Requests that the optimization be performed in Cartesian coordinates, using the Berny algorithm. Note that the initial structure may be input using any coordinate system. No partial optimization or freezing of variables can be done with purely Cartesian optimizations; the mixed optimization format with all atoms specified via Cartesian lines in the Z-matrix be used along with Opt=Z-matrix if these features are needed (see Appendix B for can details and examples). When a Z-matrix without any variables is used for the molecule specification,and Opt=Z-matrix is specified, then the optimization will actually be performed in Cartesian coordinates.


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OldRedundant

Use the Gaussian 94 redundant internal coordinate generator. Note that a variety of other coordinate systems, such as distance matrix coordinates, can be constructed using the ModRedundant option.

EstmFC

Estimate the force constants using the old diagonal guesses. Only available for the Berny algorithm. NewEstmFC

Estimate the force constants using a valence force field. This is the default. ReadFC Extract force constants from a checkpoint file. These will typically be the final

approximate force constants from an optimization at a lower level, or the force constants computed correctly by a lower-level frequency calculation (the latter are greatly preferable to the former). StarOnly

Specifies that the specified force constants are to be estimated numerically but that no optimization is to be done. This has nothing to do with computation of vibrational frequencies. In order to pass force constants estimated in this way to the MurtaughSargent program, it is necessary to do one run with Opt=StarOnly to produce the force constants, and then run the actual optimization with Opt(MS,ReadFC). FCCards

Reads the Cartesian forces and force constants from the input stream after the molecule specifications. This can be used to read force constants recovered from the Quantum Chemistry Archive using its internal FCList command. The format for this input is: • • •

Energy (format D24.16) Cartesian forces (lines of format 6F12.8) Force constants (lines of format 6F12.8)

Thenumber force constants are incoordinates. lower triangular form-(( F(J,I ) ,J=1 ,I ) ,I=1 ,NAt 3), where NAt 3 is the of Cartesian RCFC

Specifies that the computed force constants in Cartesian coordinates from a frequency calculation are to be read from the checkpoint file. This is used when the definitions of variables are changed, making previous internal coordinate force constants useless. ReadCartesianFC is a synonym for RCFC.


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CalcHFFC

Specifies that the analytic HF force constants are to be computed at the first point. CalcHFFC is used with MP2 optimizations, and it is equivalent to CalcFC for DFT methods. CalcFC

Specifies that the force constants be computed at the first point using the current method (available for the HF, MP2, CASSCF, DFT, and semi-empirical methods only). CalcAll

Specifies that the force constants are to be computed at every point using the current method (available for the HF, MP2, CASSCF, DFT, and semi-empirical methods only). Note that vibrational frequency analysis is automatically done at the converged structure and the results of the calculation are archived as a frequency job. VCD

Calculate VCD intensities at each point of a Hartree-Fock Opt=CalcAll optimization. NoRaman

Specifies that Raman intensities are not to be calculated at each point of a Hartree-Fock Opt=CalcAll job (since it includes a frequency analysis using the results of the final point of the optimization). The Raman intensities add 10-20% to the cost of each intermediate second derivative point. CONVERGENCE-RELATED OPTIONS

These options are available for the Berny algorithm only. Tight

This option tightens the cutoffs on forces and step size that are used to determine convergence. An optimization with Opt=Tight will take several more steps than with the default cutoffs. For molecular systems with very small force constants (low frequency vibrational modes), this may be necessary to ensure adequate convergence and reliability of frequencies computed in a subsequent job step. This option can only be used with Berny optimizations. For DFT calculations, Int=UltraFine should be specified as well. VeryTight

Extremely tight optimization convergence criteria. VTight is a synonym for VeryTight. For DFT calculations, Int=UltraFine should be specified as well. EigenTest EigenTest

requests and NoEigenTest suppresses testing the curvature in Berny optimizations. The test is on by default only for transition states in internal (Z?matrix) or Cartesian coordinates, for which it is recommended. Occasionally, transition state optimizations converge even if the test is not passed, but NoEigenTest is only recommended for those with large computing budgets.


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Expert

Relaxes various limits on maximum and minimum force constants and step sizes enforced by the Berny program. This option can lead to faster convergence but is quite dangerous. It is used by experts in cases where the forces and force constants are very different from typical molecules and Z-matrices, and sometimes in conjunction with Opt=CalcFC or Opt=CalcAll. NoExpert enforces the default limits and is the default. Loose

Sets the optimization convergence criteria to a maximum step size of 0.01 au and an RMS force of 0.0017 au. These values are consistent with the Int(Grid=SG1) keyword, and may be appropriate for initial optimizations of large molecules using DFT methods which are intended to be followed by a full convergence optimization using the default (Fine) grid. It is not recommended for use by itself. ALGORITHM-RELATED OPTIONS Micro

Use microiterations in ONIOM(MO:MM) optimizations. The default, with selection of L120 or L103 for the microiterations depending on whether electronic embedding is on or off. NoMicro forbids microiterations during ONIOM(MO:MM) optimizations. says to use microiterations in L120 for ONIOM(MO:MM), even for mechanical embedding. This is the default for electronic embedding. Mic103 says to perform microiterations in L103 for ONIOM(MO:MM). It is the default for mechanical embedding, and it does not work for electronic embedding. Mic120

QuadMacro

Controls the coupled, step is usedembedding during ONIOM(MO:MM) geometrywhether optimizations. This isquadratic possible macro with mechanical but not with electronic embedding. NoQuadMacro is the default. CheckCoordinates

Rebuild the connectivity matrix before each optimization step. If there is any change in it, rebuild the redundant internal coordinate system. This option is off by default. Linear Linear requests and NoLinear suppresses the linear search in Berny optimizations. The

default is to use the linear search whenever possible. TrustUpdate TrustUpdate

requests and NoTrustUpdate suppresses dynamic update of the trust radius in Berny optimizations. The default is to update for minima. RFO

Requests the Rational Function Optimization [530] step during Berny optimizations. It is the default.


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GDIIS

Specifies the use of the modified GDIIS algorithm [531,532,533]. Recommended for use with large systems, tight optimizations and molecules with flat potential energy surfaces. It is the default for semiempirical calculations. This option is turned off by the RFO and Newton options. Newton

Use the Newton-Raphson step rather than the RFO step during Berny optimizations. NRScale NRScale requests that if the step size in the Newton-Raphson step in Berny optimizations exceeds the maximum, then it is be scaled back. NoNRScale causes a minimization on

the surface of the sphere of maximum step size [534]. Scaling is the default for transition state optimizations and minimizing on the sphere is the default for minimizations. EF

Requests an eigenvalue-following algorithm Available for bothbyminima and transition states, with second, first, or no[530,535,536]. analytic derivatives as indicated CalcAll, CalcFC, the defaults, or EnOnly. EigFollow, EigenFollow, and EigenvalueFollow are all synonyms for EF. Note that when analytic gradients are available and the lowest eigenvector is being followed, then the default Berny algorithm has all of the features of the eigenvalue-following algorithm. Steep

Requests steepest descent instead of Newton-Raphson steps during Berny optimizations. This is only compatible with Berny local minimum optimizations. It may be useful when starting far from the minimum, but is unlikely to reach full convergence. UpdateMethod= keyword

Specifies the Hessian update method. Keyword is one of: Powell, BFGS, PDBFGS, ND2Corr, OD2Corr, D2CorrBFGS, Bofill, D2CMix and None. Big

Requests the optimization to be done using the fast equation solving methods [ 537] for the coordinate transformations and the Newton-Raphson or RFO step. This option is default for semiempirical calculations. This option can be turned off using Opt=Small. Large is a synonym for Big. This method avoids the matrix diagonalizations. Consequently, the eigenvector following methods (Opt=TS) cannot be used in conjunction with it. QST2 and QST3 calculations are guided using an associated surface approximation, but this may not be as effective as the normal method involving eigenvector following.


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HFError

Assume that numerical errors in the energy and forces are those appropriate for HF and PSCF calculations (1.0D-07 and 1.0D-07, respectively). This is the default for optimizations using those methods. FineGridError

Assume that numerical errors in the energy and forces are those appropriate for DFT calculations using the default grid (1.0D-07 and 1.0D-06, respectively). This is the default for optimizations using a DFT method and using the default grid (or specifying Int=FineGrid ). SEError is a synonym for this option, as these values are also appropriate for semi-empirical calculations (for which it is also the default). SG1Error

Assume that numerical errors in the energy and forces are those appropriate for DFT calculations using the SG-1 grid (1.0D-07 and 1.0D-05, respectively). This is the default for optimizations using a DFT method and Int(Grid=SG1Grid ). ReadError

Read in the accuracy to assume for the energy and forces, in format 2F10.6 (there is no terminating blank line for this input section since it is always a single line). OVERVIEW OF GEOMETRY OPTIMIZATIONS IN GAUSSIAN

By default, Gaussian performs the optimization in redundant internal coordinates. This is a change from previous versions of the program. There has been substantial controversy in recent years concerning the optimal coordinate system for optimizations. For example, Cartesian coordinates were shown to be preferable to internal coordinates (Z-matrices) for cyclic molecules [538]. Similarly, mixed internal Cartesian weresome shown to have some advantages for some cases [539] and (among them,coordinates ease of use in specifying certain types of molecules). Pulay has demonstrated [540,541,542], however, that redundant internal coordinates are the best choice for optimizing polycyclic molecules, and Baker reached a similar conclusion when he compared redundant internal coordinates to Cartesian coordinates [543]. By default, Gaussian performs optimizations via the Berny algorithm in redundant internal coordinates; these procedures are also the work of H. B. Schlegel and coworkers [149]. This optimization procedure operates somewhat differently from94those employed in electronic structure programs (including Gaussian and traditionally earlier versions): •

The choice of coordinate system for the starting molecular structure is, quite literally, irrelevant, and it has no effect on the way the optimization proceeds. All of the efficiency factors in the various coordinate systems are of no consequence, since all structures are converted internally to redundant internal coordinates.


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•

All optimizations in redundant internal coordinates are full optimizations unless variables are explicitly frozen using the ModRedundant option. Including a separate constant variable section in the molecule specification does not result in any frozen variables. Similarly, the requirement that all variables in the Z-matrix be linearly independent does not apply to these optimizations.

Optimizations in redundant internal coordinates do make use of geometry constraint information and numerical differentiation specifications. See the examples subsection for details. Optimizations in internal coordinates, which was the default procedure in Gaussian 92, is still available, via the Opt=Z-Matrix option. WAYS OF GENERATING INITIAL FORCE CONSTANTS

Unless you specify otherwise, a Berny geometry optimization starts with an initial guess for the seconddetermined derivativefrom matrix-also as athe Hessian-which is determined using connectivity atomic known radii and simple valence force field [149,544]. The approximate matrix is improved at each point using the computed first derivatives. This scheme usually works fine, but for some cases, such as Z-matrices with unusual arrangements of dummy atoms, the initial guess may be so poor that the optimization fails to start off properly or spends many early steps improving the Hessian without nearing the optimized structure. In addition, for optimizations to transition states (see also below), some knowledge of the curvature around the saddle point is essential, and the default approximate Hessian must always be improved. In these cases, there are several methods for providing improved force constants: Use force constants from a lower-level calculation: The force constants can be read from the checkpoint file (Opt=ReadFC). These will typically be the final approximate force constants from an optimization at a lower level or (much better) the force constants computed correctly at a lower level during a frequency calculation. Extract Cartesian force constants from a checkpoint file: The Cartesian (as opposed to internal) force constants can be read from the checkpoint file. Normally it is preferable to pick up the force constants already converted to internal coordinates as described above. However, a frequency calculation •

•

•

occasionally reveals a molecule distort toconstraints lower symmetry. this means that a newthat Z-matrix with needs fewer to symmetry must beUsually specified to optimize to the lower energy structure. In this case the computed force constants in terms of the old Z-matrix variables cannot be used, and instead the command Opt=RCFC is used to read the Cartesian force constants and transform them to the current Z-matrix variables. Note that Cartesian force constants are only available on the checkpoint file after a frequency calculation. You cannot use this option after an optimization dies


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•

•

•

because of a wrong number of negative eigenvalues in the approximate second derivative matrix. In that case, you may want to start from the most recent geometry and compute some derivatives numerically. Calculate initial force constants at the HF level : You can also request that the analytic Hartree-Fock second derivatives be calculated at the first point of the optimization. can be used with HF, DFT. Note or post-SCF This is done byThis specifying that thisgradient option isoptimizations. equivalent to Opt=CalcHFFC CalcFC for DFT methods. Calculate initial force constants at the current level of theory: You can request that the second derivatives of the method being used in the optimization be computed at the first point by specifying Opt=CalcFC. This is only possible for HF, DFT, MP2, and semi-empirical methods. Calculate new force constants at every point : Normally after the initial force constants have been decided upon, they are updated at each point using the gradient information available from the points done in the optimization. For a Hartree-Fock, MP2, or semi-empirical optimization, you can specify Opt=CalcAll , whichNeedless requeststothat second be computed at every point in the optimization. say, this isderivatives very expensive.

•

Input new guesses: The default approximate matrix can be used, but with new

guesses read in for some or all of the diagonal elements of the Hessian. This is specified in the ModRedundant input or on the variable definition lines in the Zmatrix. For example: Redundant Internals 1 2 3 104.5 1 2 1.0 H 0.55 •

• •

Z-matrix A 104.5 R 1.0 H 0.55

The first line specifies that the angle formed by atoms 1, 2 and 3 (the variable A in the Z-matrix) is to start at the value 104.5, and the second line sets the initial value of the bond between atoms 1 and 2 (the variable R in the Z-matrix) to 0.55 Angstroms. The letter H on the second line indicates that a diagonal force constant is being specified for this coordinate and that its value is 0.55 hartree/au 2. Note that the units here are Hartrees and Bohrs or radians. This option is valid only with the Berny algorithm. Compute some or all of the Hessian numerically: You can ask the optimization program to compute part of the second derivative matrix numerically. In this case each specified variable will be stepped in only one direction, not both up and down as would be required for an accurate determination of force constants. The resulting second-derivatives are not as good as those determined by a frequency calculation but are fine for starting an optimization. Of course, this requires that the program do an extra gradient calculation for each specified variable. This procedure is requested by a flag (D) on the variable definition lines: Redundant Internals 1 2 1 2

2 3 2 3

1.0 D 1.5 3 104.5 D 4 110.0


Z-matrix R1 R2 A1 A2

1.0 1.5 104.5 D 110.0

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•

This input tells the program to do three points before taking the first optimization step: the usual first point, a geometry with the bond between atoms 1 and 2 ( R1) incremented slightly, and a geometry with the angle between atoms 1, 2 and 3 ( A1) incremented slightly. The program will use the default diagonal force constants for the other two coordinates and will estimate all force constants (on A1 from the three points. This and offisdiagonal) for bond(1,2)/ and and angle(1,2,3)/ option only available with the R1 Berny EF algorithms.

OPTIMIZING TO A TRANSITION STATE OR HIGHER-ORDER SADDLE POINT Transition State Optimizations Using Synchronous Transit-Guided Quasi-Newton (STQN) Methods. Gaussian includes the STQN method for locating transition

structures. This method, implemented by H. B. Schlegel and coworkers [149,150], uses a quadratic synchronous transit approach to get closer to the quadratic region of the transition state and then uses a quasi-Newton or eigenvector-following algorithm to complete the optimization. the default algorithm for minimizations, it performs optimizations by default in Like redundant internal coordinates. This method will converge efficiently when provided with an empirical estimate of the Hessian and suitable starting structures. This method is requested with the QST2 and QST3 options. QST2 requires two molecule specifications, for the reactants and products, as its input, while QST3 requires three molecule specifications: the reactants, the products, and an initial structure for the transition state, in that order. The order of the atoms must be identical within all molecule specifications. See the examples for sample input for and output from this method. Despite the superficial similarity, this method is verystructures differentrequested from the Linear Synchronous Transit method for locating transition with the nowdeprecated LST keyword. Opt=QST2 generates a guess for the transition structure that is midway between the reactants and products in terms of redundant internal coordinates, and it then goes on to optimize that starting structure to a first-order saddle point automatically. The Linear Synchronous Transit method merely locates a maximum along a path connecting two structures which may be used as a starting structure for a subsequent manually-initiated transition state optimization; LST does not locate a proper stationary point . In contrast, QST2 and QST3 do locate proper transition states. Traditional Transition State Optimizations Using the Berny Algorithm . The Berny

optimization program canThe alsooptions optimize a saddle using internal coordinates, is coaxed along properly. to to request thispoint procedure are Opt=TS for a if it transition state (saddle point of order 1) or Opt(Saddle= N ) for a saddle point which is a maximum in N directions. When searching for a local minimum, the Berny algorithm uses a combination of rational function optimization (RFO) and linear search steps to achieve speed and reliability (as described below). This linear search step cannot be applied when searching for a


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transition state. Consequently, transition state optimizations are much more sensitive to the curvature of the surface. A transition state optimization should always be started using one of the options described above for specifying curvature information. Without a full second derivative matrix the initial step is dependent on the choice of coordinate system, so it is best to try to make the reaction coordinate (direction of negative curvature) correspond to one or two redundant internal coordinates or Z-matrix variables (see the examples below). In the extreme case in which the optimization begins in a region known to have the correct curvature (e.g., starting with Opt=CalcFC) and steps into a region of undesirable curvature, the Opt=CalcAll option may be useful. This is quite expensive, but the full optimization procedure with correct second derivatives at every point will usually reach a stationary point of correct curvature if started in the desired region. For suggestions on locating transition structures, refer to the literature [148]. An eigenvalue-following (mode walking) optimization method [146,147] can be Opt=EF requested by RFO superior to the method in Gaussian but since the step. This [530]was has sometimes now been incorporated intoBerny the Berny algorithm, EF is88, seldom preferable unless its ability to follow a particular mode is needed, or gradients are not available (in which case Berny can't be used anyway). This algorithm has a dimensioning limit of 50 active variables. By default, the lowest mode is followed. This is correct when already in a region of correct curvature and when the softest mode is to be followed uphill. This default can be overridden in two ways: •

The mode having the largest magnitude component for a specific Z-matrix variable can be requested by placing a 4 on the variable definition line: Ang1 104.5 4

•

The N th mode in order of increasing Hessian eigenvalue can be requested by placing a 10 after the N th variable definition line, as in this input file: # Opt=(EF,TS) HCN --> HNC transition state search This job deliberately follows the wrong (second) mode! 0,1 N C,1,CN H,1,CH,2,HCN CN 1.3 CH 1.20 10 Requests the second mode. HCN 60.0

By default, the Berny optimization program checks the curvature (number of negative eigenvalues) of its approximate second derivative matrix at each step of a transition state optimization. If the number is not correct (1 for a transition state), the job is aborted. A


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search for a minimum will often succeed in spite of bad real or approximate curvature, because the steepest descent and RFO parts of the algorithm will keep the optimization moving downward, although it may also indicate that the optimization has moved away from the desired minimum and is headed through a transition state and on to a different minimum. On the other hand, a transition state optimization has less chance of success if the curvature isoption. wrongIf atNoEigenTest the current point. However, thetotest can be suppressed with the is used, it is best to a small value NoEigenTest MaxCycle (e.g. 5) and check the structure after a few iterations. THE BERNY OPTIMIZATION ALGORITHM

The Berny geometry optimization algorithm in Gaussian is based on an earlier program written by H. B. Schlegel which implemented his published algorithm [136]. The program has been considerably enhanced since this earlier version using techniques either taken from other algorithms or never published, and consequently it is appropriate to summarize the current status of the Berny algorithm here. At each step of a Berny optimization the following actions are taken: •

•

•

•

•

The Hessian is updated unless an analytic Hessian has been computed or it is the first step, in which case an estimate of the Hessian is made. Normally the update is done using an iterated BFGS for minima and an iterated Bofill for transition states in redundant internal coordinates, and using a modification of the original Schlegel update procedure for optimizations in internal coordinates.By default, this is derived from a valence force field [544], but upon request either a unit matrix or a diagonal Hessian can also be generated as estimates. The trust radius (maximum allowed Newton-Raphson step) is updated if a minimum is sought, using the method Fletcher [545,546,547]. Any components of the gradient vectorofcorresponding to frozen variables are set to zero or projected out, thereby eliminating their direct contribution to the next optimization step. If a minimum is sought, perform a linear search between the latest point and the best previous point (the previous point having lowest energy). If second derivatives are available at both points and a minimum is sought, a quintic polynomial fit is attempted first; if it does not have a minimum in the acceptable range (see below) or if second derivatives are not available, a constrained quartic fit is attempted. This fits a quartic polynomial to the energy and first derivative (along the connecting line) at the two points with the constraint that the second derivative of theitself polynomial just one reachminimum. zero at itsIfminimum, ensuring that the polynomial has exactly this fit failsthereby or if the resulting step is unacceptable, a simple cubic is fit is done Any quintic or quartic step is considered acceptable if the latest point is the best so far but if the newest point is not the best, the linear search must return a point in between the most recent and the best step to be acceptable. Cubic steps are never accepted unless they are in between the two points or no larger than the previous step. Finally, if all fits fail and the most recent step is the best so far, no


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•

•

•

•

linear step is taken. If all fits fail and the most recent step is not the best, the linear step is taken to the midpoint of the line connecting the most recent and the best previous points. If the latest point is the best so far or if a transition state is sought, a quadratic step is determined using the current (possibly approximate) second derivatives. If a linear search wassearch done,and the uses quadratic is taken the point extrapolated using the linear forcesstep at that pointfrom estimated by interpolating between the forces at the two points used in the linear search. By default, this step uses the Rational Function Optimization (RFO) approach [146,147,530,536]. The RFO step behaves better than the Newton-Raphson method used in earlier versions of Gaussian when the curvature at the current point is not that desired. The old Newton-Raphson step is available as an option. Any components of the step vector resulting from the quadratic step corresponding to frozen variables are set to zero or projected out. If the quadratic step exceeds the trust radius and a minimum is sought, the step is reduced in length to the trust radius by searching for a minimum of the quadratic on state the sphere having trust radius, as discussed Jorgensen afunction transition is sought or if the NRScale was requested, theby quadratic step[534]. is If simply scaled down to the trust radius. Finally, convergence is tested against criteria for the maximum force component, root-mean square force, maximum step component, and root-mean-square step. The step is the change between the most recent point and the next to be computed (the sum of the linear and quadratic steps).

CHANGE IN TRADITIONAL CONVERGENCE CRITERIA BEGINNING WITH GAUSSIAN 98

Gaussian 98 introduced one small but significant change in the criteria for determining

when a geometry has converged. When the forces are two orders of magnitude smaller than the cutoff value (i.e., 1/100th of the limiting value), then the geometry is considered converged even if the displacement is larger than the cutoff value. This test was introduced to facilitate optimizations of large molecules which may have a very flat potential energy surface around the minimum. The generation of redundant internal coordinates for weakly bound complexes was also updated with Gaussian 98. We include Hydrogen bonds automatically. In addition, in connecting different fragments which are only weakly bound (hydrogen-bonded and otherwise), all pairs of atoms with one atom in each fragment having distance within a factor 1.3pairs of theare closest have their distances added to the internal coordinates. least 3of such found,pair then no angles or dihedrals involving both fragments are If at added. However, if only 1 or two pairs of atoms are close, then the related angles and dihedrals are added in order to ensure a complete coordinate system. As usual, the ModRedundant option can be used to add or remove any coordinates manually.


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Analytic gradients are available for the HF, all DFT methods, CIS, MP2, MP3, MP4(SDQ), CID, CISD, CCD, CCSD, QCISD, CASSCF, and all semi-empirical methods. The Tight, VeryTight, Expert, Eigentest and EstmFC options are available for the Berny algorithm only.

IRC, Scan, Force

The examples in the subsection will focus on normal optimization procedures in Gaussian 03. However, at the end of the subsection, examples illustrating traditional, Zmatrix-based optimizations using the Berny algorithm will also be given. Basic Optimization Input. Traditionally, geometry optimizations required a Z-matrix

specifying both the starting geometry and the variables to be optimized. For example, the input file in the left column below could be used for such an optimization on water: # HF/6-31G(d) Opt Test

# HF/6-31G(d) Opt Test

Water opt

Water opt

0 1 O1 H1 O1 R H2 O1 R H1 A Variables: R=1.0 A=104.5

0 O H H

1 0.00 0.00 0.97

0.00 0.00 0.00 1.00 0.00 -0.25

This Z-matrix specifies the starting configuration of the nuclei in the water molecule. It also specifies that the optimization should determine the values of R and A which minimize the energy. Since the OH bond distance is specified using the same variable for both hydrogen atoms, this Z-matrix also imposes (appropriate) symmetry constraints on the molecule. The Cartesian coordinate input in the right column is equivalent to the Z-matrix in the left column. In early versions of Gaussian, such input would lead to an optimization performed in Cartesian coordinates; however, by Gaussian 92, Z-matrix input could be used for optimizations in either coordinate system. By contrast, beginning with Gaussian 98 these two input files are exactly equivalent , and this holds for Gaussian 03 as well. They both will result in a Berny optimization in redundant internal coordinates, giving identical final output.


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Output from Optimization Jobs. The string GradGradGrad... delimits the output from

the Berny optimization procedures. On the first, initialization pass, the program prints a table giving the initial values of the variables to be optimized. For optimizations in redundant internal coordinates, all coordinates in use are displayed in the table (not merely those present in the molecule specification section): GradGradGradGradGradGradGradGradGradGradGradGradGradGradGradGradGrad Berny optimization. The opt. algorithm is identified by the header format & this line. Initialization pass. ---------------------------! Initial Parameters ! ! (Angstroms and Degrees) ! ------------------------------------------! Name Definition Value Derivative Info. ! ----------------------------------------------------------------------! R1 R(2,1) 1. estimate D2E/DX2 ! ! R2 R(3,1) 1. estimate D2E/DX2 ! ! A1 A(2,1,3) 104.5 estimate D2E/DX2 ! --------------------------------------------------------------------

The manner in which the initial second derivative are provided is indicated under the heading Derivative Info. In this case the second derivatives will be estimated. Each subsequent step of the optimization is delimited by lines like these: GradGradGradGradGradGradGradGradGradGradGradGradGradGradGradGradGrad Berny optimization. Search for a local minimum. Step number 4 out of a maximum of 20

Once the optimization completes, the final structure is displayed: Optimization completed. -- Stationary point found. ---------------------------! Optimized Parameters ! ! (Angstroms and Degrees) ! --------------------------------------! Name Definition Value Derivative Info. ! ----------------------------------------------------------------------! R1 R(2,1) 0.9892 -DE/DX = 0.0002 ! ! R2 R(3,1) 0.9892 -DE/DX = 0.0002 ! ! A1 A(2,1,3) 100.004 -DE/DX = 0.0001 ! -----------------------------------------------------------------------

The redundant internal coordinate definitions are given in the second column of the table. The numbers in parentheses refer to the atoms within the molecule specification. For example, the variable R1, defined as R (2,1), specifies the bond length between atoms 1 and 2.


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When a Z-matrix was used for the initial molecule specification, this output will be followed by an expression of the optimized structure in that format, whenever possible. The energy for the optimized structure will be found in the output from the final optimization step, which precedes this table in the output file. More detailed information about the out put from geometry optimizations is provided in Chap. 3 of Exploring Chemistry with Electronic Structure Methods . Compound Jobs. Optimizations are commonly followed by frequency calculations at the optimized structure. To facilitate this procedure, the Opt keyword may be combined with Freq in the route section of an input file, and this combination will automatically

generate a two-step job. It is also common to follow an optimization with a single point energy calculation at a higher level of theory. The following route section automatically performs an HF/631G(d,p) optimization followed by an MP4/6-31G(d,p) single point energy calculation # MP4/6-31G(d,p)//HF/6-31G(d,p) Test

Note that the Opt keyword is not required in this case. However, it may be included if setting any of its options is desired. Specifying Redundant Internal Coordinates. The following input file illustrates the

method for specifying redundant internal coordinates within an input file: # HF/6-31G(d) Opt=ModRedun Test Opt job 0,1 C1 0.000 C2 0.000 O3 1.047 H4 -1.000 H5 -0.735 H6 -0.295 O7 1.242 H8 1.938 3

8

2

1

0.000 0.000 0.000 -0.006 0.755 -1.024 0.364 -0.001

0.000 1.505 -0.651 -0.484 1.898 1.866 2.065 1.499

3

This structure is acetaldehyde with an OH substituted for one of the hydrogens in the methyl group; the first input line for ModRedundant creates a hydrogen bond between that hydrogen atom and the oxygen atom in the carbonyl group. Note that this line adds only the bond between these two atoms. The associated angles and dihedral angles would need to be added as well if they were desired.


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Displaying the Value of a Desired Coordinate . The second input line for ModRedundant specifies the C-C=O bond angle, ensuring that its value will be

displayed in the summary structure table for each optimization step. Using Wildcards in Redundant Internal Coordinates. A distance matrix coordinate

system can be activated using the following input: * * B * * * K

Define all bonds between pairs of atoms Remove all other redundant internal coordinates

The following input defines partial distance matrix coordinates to connect only the closest layers of atoms: * * B 1.1 * * * K

Define all bonds between atoms within 1.1 Å Remove all other redundant internal coordinates

The following input sets up an optimization in redundant internal coordinates in which atoms N1 through Nn are frozen (such jobs may require the NoSymm keyword). Note that the lines containing the B action code will generate Cartesian coordinates for all of the coordinates involving the specified atom since only one atom number is specified: N1 B ... Nn B * F

Generate Cartesian coordinates involving atom N1 Generate Cartesian coordinates involving atom Nn Freeze all Cartesian coordinates

The following input defines special "spherical" internal coordinate appropriate for molecules like C60 [548] by removing all dihedral angles from the redundant internal coordinates: * * * * R

Remove all dihedral angles

The following input rotates the group about the N2-N3 bond by 10 degrees: * N2 N3 * +=10.0

Add 10.0 to the values to dihedrals involving N2-N3 bond

Additional examples are found in the section on relaxed PES scans below. Performing Partial Optimizations. The following job illustrates the method for freezing

variables during a redundant internal coordinate optimization: # HF/6-31G* Opt=ModRedundant Test Partial optimization 1 1 C H 1 R1 H 1 R1 2 A1 O 1 R2 2 A2 3 120.0


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H 4 R3 3 A3 2 180.0 A1=120.0 ... R3=1.1 4 5 5 4 3 2

1.3 F F

The structure is specified as a traditional Z-matrix, with its variables defined in a separate section. The final input section gives the values for the ModRedundant option. This input fixes the O-H bond and the dihedral angle for the final hydrogen atom. Note that any value specified in this manner need not be the same as the one listed in the preceding Z-matrix (as is the case for the O-H bond length); the structure is adjusted to enforce this constraint. The constrained value is optional. For example, in this case the value of second modified redundant internal coordinate defaults to the value from the Z-matrix (180.0). Modifying Optimized Structures (Why You Don't Need a Z-matrix) . Use the

Cartesian coordinates version of the optimized structure as your starting point. It can be generated by a route like this one: # Guess=Only Geom=Check

(It can also be extracted from an archive entry.) Once you have the structure in Cartesian coordinates, you can use it in a variety of ways: •

Add and/or remove atoms from it . Additional atoms may be specified in either

Cartesian or •

internal coordinates.

Modify it by substituting atoms or groups: For example, you could change a

hydrogen to a methyl group by editing the structure, replacing the desired hydrogen with a carbon atoms, and then adding three additional hydrogen atoms bonded to that carbon. The latter could be given in internal coordinates: H6 1.2 2.3 1.1 H7 1.2 0.0 -.9 H8 0.0 -.9 0.0

H6 1.2 2.3 1.1 C7 1.2 0.0 -.9 H8 0.0 -.9 0.0 H9 C7 R H5 A C2 180.0 H10 C7 R H6 A C2 180.0 H11 C7 R H8 A C2 -180.0 R=1.0 A=120.0 7 2 1.5

The new structure on the right also uses an additional redundant internal coordinate (specifying Opt=ModRedundant on the final job) to alter the bond distance for the new carbon atom which is replacing the hydrogen (bonded to atom 2). If all you want to do is change the value or activate/frozen status of one or more variables, then you can use Geom=ModRedundant rather than this approach.


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Restarting an Optimization. A failed optimization may be restarted

from its checkpoint file by simply repeating the route section of the original job, adding the Restart option to the Opt keyword. For example, this route section restarts a Berny optimization to a second-order saddle point: # RHF/6-31G(d) Opt=(Saddle=2,Restart,MaxCyc=50) Test

Reading a Structure from the Checkpoint File . Redundant internal coordinate structures may be retrieved from the checkpoint file with Geom=Checkpoint as usual. The read-in structure may be altered by specifying Geom=ModRedundant as well; modifications have a form identical to the input for Opt=ModRedundant :

[Type] N 1 [ N 2 [ N 3 [ N 4]]] [[+=]Value] [ Action [ Params]] [[Min] Max]] Locating a Transition Structure with the STQN Method . The QST2 option initiates a

search for a transition structure connecting specific reactants and products. The input for this option has this general structure: # HF/6-31G(d) Opt=QST2 (Opt=QST2,ModRedun) First title section Molecule specification for the reactants for the reactants Second title section the reactants Molecule specification for the products

# HF/6-31G(d)

First title section Molecule specification

ModRedundant input for

Second title section Molecule specification

for the products ModRedundant input for the products (optional)

Note that each molecule specification is preceded by its own title section (and separating blank line). If the ModRedundant option is specified, then each molecule specification is followed by any desired modifications to the redundant internal coordinates. Gaussian will automatically generate a starting structure for the transition structure

midway between the reactant and product structures, and then perform an optimization to a first-order saddle point. The QST3 option allows you to specify a better initial structure for the transition state. It requires the two title and molecule specification sections for the reactants and products as for QST2 and also additional, third title and molecule specification sections for the initial transition state geometry (along with the usual blank line separators), as well as three corresponding modifications to the redundant internal coordinates if the ModRedundant


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option is specified. The program will then locate the transition structure connecting the reactants and products closest to the specified initial geometry. The optimized structure found by QST2 or QST3 appears in the output in a format similar to that for other types of geometry optimizations: ---------------------------! Optimized Parameters ! ! (Angstroms and Degrees) ! ----------------------------------------! Name Definition Value Reactant Product Derivative Info. ! -------------------------------------------------------------------! R1 R(2,1) 1.0836 1.083 1.084 -DE/DX = 0. ! ! R2 R(3,1) 1.4233 1.4047 1.4426 -DE/DX = -0. ! ! R3 R(4,1) 1.4154 1.4347 1.3952 -DE/DX = -0. ! ! R4 R(5,3) 1.3989 1.3989 1.3984 -DE/DX = 0. ! ! R5 R(6,3) 1.1009 1.0985 1.0995 -DE/DX = 0. ! ! ... ! --------------------------------------------------------------------

In addition to listing the optimized values, the table includes those for the reactants and products. Performing a Relaxed Potential Energy Surface Scan . The Opt=Z-matrix and Opt=ModRedundant keywords may also be used to perform a relaxed potential energy

surface (PES) scan. Like the scan facility provided by previous versions of Gaussian, a relaxed PES scan steps over a rectangular grid on the PES involving selected internal coordinates. It differs from the operation of the Scan keyword in that a constrained geometry optimization is performed at each point. Relaxed PES scans are available only for the Berny algorithm. If any scanning variable breaks symmetry during the calculation, then you must include NoSymm in the route section of the job, or it will fail with an error. Redundant internal coordinates specified with the Opt=ModRedundant option may be scanned using the S code letter: N 1 N 2 [ N 3 [ N 4]] [[+=]value] S steps step-size. For example, this input adds a bond between atoms 2 and 3, setting its initial value to 1.0 Å, and specifying three scan steps of 0.05 Å each: 2 3 1.0 S 3 0.05

Wildcards in the ModRedundant input may also be useful in setting up relaxed PES scans. For example, the following input is appropriate for a potential energy surface scan involving the N1-N2-N3-N4 dihedral angle. Note that all other dihedrals around the bond should be removed: * N2 N3 * R N1 N2 N3 N4 S 20 2.0

Remove all dihedrals involving the N2-N3 bond Specify a relaxed PES scan of 20 steps in 2º increments


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Full vs. Partial Optimizations. When it is performed in internal (Z-matrix) coordinates,

the Berny optimization algorithm makes a distinction between full and partial optimizations. Full optimizations optimize all specified variables in order to find the lowest energy structure, while partial optimizations optimize only a specified subset of the variables. Note that the FOpt keyword form is used to request that the optimization variables be tested for linear independence prior to beginning the optimization. Those variables whose values should be held fixed are specified in a separate input section, separated by the usual variables section by a blank line or a line containing a space in the first column and the string Constants:. For example, the following input file will optimize only the bond distance R , but not the angle A, which will be held fixed at 105.4 degrees throughout the optimization: # HF/6-31G(d) Opt=Z-matrix Test Partial optimization for water 0 1 O H1 O R H2 O R H1 A Variables: R 1.0 Constants: A 105.4

Breaking Symmetry During an Optimization in Internal Coordinates. Below are two

geometry forvariable water. The onefor onboth the left haslengths, been constrained C2v always symmetry;specifications since the same is used bond their valuestowill be the same: O H 1 R1 H 1 R1 2 A

O H 1 R1 H 2 R2 2 A

R1=0.9 A=105.4

R1=0.9 R2=1.1 A=105.4

By contrast, the Z-matrix on thehaving right isdifferent unconstrained since the twothat bond are specified by different variables initial values. Note anlengths optimization in redundant internal coordinates which begins from a C2v structure will retain that symmetry throughout the optimization. Relaxed PES Scans. For Opt=Z-matrix, a relaxed PES scan is requested simply by tagging the Z-matrix variables whose values are to be incremented with the S code letter


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and the number of steps and the increment size. For example, the following input file requests a relaxed PES scan for the given molecule: # HF/6-31G(d) Opt=Z-matrix Test Relaxed PES scan 0 1 O H 1 R1 C 1 R2 2 A2 ... Variables: R1 0.9 S 5 0.05 R2 1.1 A2 115.4 S 2 1.0 ...

This causes the variable R1 to be incremented five times, by 0.05 Å each time, and the variable A2 to be incremented twice, by 1 degree each time, resulting in a total of 18 geometry optimizations (the initial values for each variable also constitute a point within the scan).

Output The Output keyword requests output of Fortran unformatted files. Its options control the contents of the created file.

WFN

Write a PROAIMS wavefunction (.wfn) file. The name for the created file is read from the input stream, on a separate line. PSI is a synonym for WFN. Pickett

Write g tensors and other tensors for hyperfine spectra [272,273,274,275,277,279] to the output file in the form of input for Pickett's program [280] (see spec.jpl.nasa.gov). The following tensors can be computed by Gaussian 03 [207,212,213,214,276,278]: • • • • • •

Nuclear electric quadrupole constants: all jobs Rotational constants: Freq=(VibRot[,Anharmonic]) Quartic centrifugal distortion terms: Freq=(Anharmonic) Electronic spin rotation terms: NMR Nuclear spin rotation terms: NMR Dipolar hyperfine terms: all jobs


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•

Fermi contact terms: all jobs

ReadAtoms

Read a list of the atoms to include in the input for Pickett's program (note that this program only accepts tensors for eight nuclei). Atoms numbers are specified in free format, and this input section By default, eight "interesting" atoms are selected automatically by is theblank-terminated. program.

Punch

OVGF These method keywords request an Outer Valence Green's Function (propagator) calculation of correlated electron affinities and ionization potentials [243,244,245,246,247,248,249,549]. OVGF calculations default to storage of integrals, but can be run Tran=Full to save CPU time at the expense of disk usage, or with Tran=IJAB to save on disk space at

the expense of CPU time. In the latter case, electron affinities are not computed. By default, only ionization potentials which are < 20 eV are computed. Use ReadOrbitals option to specify the starting and ending orbitals to refine as input. By default, all orbitals are used.

FC

The frozen-core options for defining inner-shells to be excluded from the correlation calculation are valid with this keyword. See the discussion here for details. ReadOrbitals

Specify starting and ending orbitals to refine, in a separate, blank-terminated input section. For unrestricted calculations, separate ranges are specified for alpha and beta orbitals (on the same input line).

Single point energy calculations only.


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For OVGF calculations, the results for each orbital appear as follows: Summary of results for alpha spin-orbital

6

P3:

Koopmans theorem: -0.72022D+00 au -19.598 eV Converged second order pole: -0.61437D+00 au -16.718 eV 0.840 (PS) Converged 3rd order P3 pole: -0.63722D+00 au -17.340 eV 0.854 (PS)

The second output line gives the estimate of ionization potential/electron affinity for the specified orbital (which property is given depends on whether the orbital is occupied or not, respectively) . The pole strength is a measure of how easy it is to make this excitation, with 1.0 as the maximum value. Note that orbitals are listed in the output in order of symmetry (and not necessarily in numerical order).

PBC This keyword allows you to specify options for Periodic Boundary Conditions jobs. Note PBC is turned on simply by including translation vectors in the input structure, and this keyword is used only to control how PBC calculations are performed. If you do not need any of these options, you do not have to include the keyword to perform a PBC calculation.

GammaOnly

Do just the Γ point (k=0) rather than full k-integration. NKPoint= N

Do approximately N k-points. CellRange= N

Go out N Bohr in each direction in setting up image cells. NCellMin= N

Include at least N cells. NCellMax= N

Include at most N cells in any part of the calculation. NCellDFT= N

Include at least N cells in DFT XC quadrature. NCellXC is a synonym for this option.


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NCellK = N

Include at least N cells in exact exchange. By default, if exact exchange is included, then this is twice the number of cells used for overlap-related quantities and XC quadrature.

See the "Specifying Periodic Systems" subsection of the "Overview of Molecule Specifications" section.

PM3 PM3MM The method keywords request a semi-empirical calculation using the PM3 Hamiltonian [55,56]. The parameter for Li has been updated as specified in [402]. PM3MM specifies the PM3 model including the optional molecular mechanics correction for HCON linkages. No basis set keyword should be specified with either of these keywords.


The PM3 energy appears in the output file as follows (followed by the x, y, and z components of the dipole moment): Energy= -.080731473251 NIter= 10. Dipole moment= .000000 .000000 -.739540

The energy is as defined by the PM3 semi-empirical model. Note that energy differences computed from the values in semi-empirical calculations are in Hartrees and may be compared directly with energy differences computed from jobs using other methods.

Polar This method keyword requests that the dipole electric field polarizabilities (and hyperpolarizabilities, if possible) be computed. No geometry change or derivatives are implied, but this keyword may be combined in the same job with numerical


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differentiation of forces by specifying both Freq and Polar in the route section. Freq and Polar may not be combined for methods lacking analytic gradients (MP4(SDTQ), QCISD(T), CCSD(T), BD, and so on). Note that Polar is done by default when second derivatives are computed analytically. Normally, polarizabilities and hyperpolarizabilities computed using static frequencies. However, frequency-dependent polarizabilities and are hyperpolarizabilities [220,221,222,224,225] may be computed by including CPHF=RdFreq in the route section and specifying the desired frequency in the input file. Optical rotations [261,262,263,264,265,266,550,551,552,553] may also be predicted via the OptRot option [223,267,268,269,270,271,305,554].

OptRot

Perform optical rotation calculation. DCSHG

Do extra frequency-dependent CPHF for dc-SHG (direct current second harmonic generation) hyperpolarizabilities. This option implies CPHF=RdFreq as well. Step= N

Specifies the step size in the electric field to be 0.0001 N atomic units. Analytic

Analytically compute the polarizability and, if possible, the hyperpolarizability. This is possible for RHF and UHF and MP2 for which it is the default. The polarizability is always computed during analytic frequency calculations. Cubic

Numerically differentiate analytic polarizabilities to produce hyperpolarizabilities. Numerical

Computes the polarizability as a numerical derivative of the dipole moment (itself the analytic derivative of the energy, of course, not the expectation value in the case of MP2 or CI energies). The default for methods for which only analytic first derivatives are available. EnOnly

Requests double numerical differentiation of energies to produce polarizabilities. EnergyOnly, a synonym for EnOnly, is a misnomer, since analytic first derivatives will also be differentiated twice, to produce hyperpolarizabilities, when they are available. Restart

Restarts a numerical polarizability calculation from the checkpoint file. A failed Polar


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calculation may be restarted from its checkpoint file by simply repeating the route section of the original job, adding the Restart option to the Polar keyword. No other input is required. Dipole

Compute the dipole polarizabilities (this is the default).

Polarizabilities and hyperpolarizabilities will be automatically computed for HF and MP2. Polar will compute polarizabilities only, and Polar=EnOnly will produce both polarizabilities and hyperpolarizabilities for CIS, MP2, MP3, MP4(SDQ), CID, CISD, CCD, CCSD, QCISD, CASSCF and DFT methods. Polar will produce only polarizabilities for all other methods (for which no analytic derivatives are available, making EnOnly the default). Note that Polar is not available for any semi-empirical method.

Freq CPHF=RdFreq

Frequency-Dependent Properties. The following job will frequency-dependent

polarizabilities and hyperpolarizabilities using ω=0.1 Hartrees: # Polar CPHF=RdFreq HF/6-31G(d) Frequency-dependent calculation: w=0.1

Molecule specification 0.1

Performing a frequency-dependent Polar calculation results in the results for the specified frequency following those for the static case within the output. For example, here are the polarizability values for a frequency-dependent job (ω=0.1 Hartree): SCF Polarizabilityfor W= 0.000000: 1 2 3 1 0.482729D+01 2 0.000000D+00 0.112001D+02 3 0.000000D+00 0.000000D+00 0.165696D+02 Isotropic polarizability for W= 0.000000 10.87 Bohr**3 SCF Polarizability for W= 0.100000: 1 2 3 1 0.491893D+01 2 0.000000D+00 0.115663D+02


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3 0.000000D+00 0.000000D+00 0.171826D+02 Isotropic polarizability for W= 0.100000 11.22 Bohr**3.

A static polarizability calculation would include only the first section. Similar output follows for hyperpolarizabilities and additional properties. Optical Rotations. Here is the key part of

the output for optical rotations jobs (OptRot option). In this case, we have performed a frequency-dependant calculation by including CPHF=RdFreq in the route section and specified a frequency of 500 nm: w= 0.000000 a.u., Optical Rotation Beta= 1.2384 au. Molar Mass = 74.4103 grams/mole,[Alpha]D = 643.30 deg. G' tensor for W= 0.091127: -27.88112715 8.27183975 58.48555729 -7.74920313 9.64293589 28.50024234 -14.62301919 4.52918305 10.26760578 w= 0.091127 a.u., Optical Rotation Beta= 2.6569 au. Molar Mass = 74.4103 grams/mole, [Alpha] ( 5000.0 A) = 1917.10 deg.

The static results are listed first in the output (ω=0.0), followed by those for the specified frequency. The specific rotation value is highlighted in the output.

Population

This properties keyword controls printing of molecular orbitals and several types of population analysis and atomic charge assignments. The default is for to print justthethedefault total is atomic charges and orbital energies, except for Guess=Only jobs, which Pop=Full (see below). Populations are done once for single-point calculations and at the first and last points of geometry optimizations. The density that is used for the population analysis is controlled by the Density keyword. Note that only one density and method of charge fitting can be used in a job step. If several combinations are of interest, additional jobs steps can be added which specify Guess=Only Density=Check , to avoid repeating any costly calculations. Population analysis results are given in the standard orientation. Output controlled by the Pop keyword includes: • • •

Molecular orbitals and orbital energies Atomic charge distribution Multipole moments: dipole through hexadecapole


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By default, Gaussian prints molecular orbitals and performs population analyses regarding the MO coefficients from a semi-empirical calculation as coefficients of orthogonalized atomic orbitals (OAO's). There are important theoretical reasons for preferring this interpretation, but some other semi-empirical programs interpret these coefficients as referring to raw atomic orbitals. Use IOp(4/24=3) to compare orbitals from semi-empirical calculations to the results of such other programs.

None

No orbitals are printed, and no population analysis is done. Minimal

Total atomic charges and orbital energies are printed. This is the default for all job types except Guess=Only. Regular

The five highest occupied and five lowest virtual orbitals are printed, along with the density matrices and a full (orbital by orbital and atom by atom) Mulliken population analysis. Since the size of the output depends on the square of the size of the molecule, it can become quite substantial for larger molecules. Full

Same as the Regular population analysis, except that all orbitals are printed. BONDING ANALYSIS OPTION Bonding

Do a bonding population analysis in addition to the standard analysis. This is a Mulliken population analysis in which only density terms involving pairs of basis functions on different centers are retained. The other options control how much is printed. NATURAL ORBITAL-RELATED OPTIONS NaturalOrbitals

Do a natural orbital analysis of the total density. NO is a synonym for NaturalOrbitals . NOAB

Do separate natural orbital analyses for the α and β densities. NaturalSpinOrbitals is a synonym for NOAB. AlphaNatural

Do separate natural orbital analyses for the α and β densities, but store only the α densities for use in a .wfn file (see Output=WFN). NOA is a synonym for AlphaNatural .


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BetaNatural

Do separate natural orbital analyses for the α and β densities, but store only the β densities for use in a .wfn file (see Output=WFN). NOB is a synonym for BetaNatural. SpinNatural

Generate natural orbitals for the spin density (with α considered positive). By default, natural orbitals are not included in the checkpoint file. Use a second job step of this form to place the natural orbitals into the checkpoint file: --Link1-%Chk=name # Guess=(Read,Save,Only,NaturalOrbitals) Geom=AllCheck

Run the formchk utility on the resulting checkpoint file to prepare the orbitals for visualization.

MK

Produce charges fit to the electrostatic potential at points selected according to the MerzSingh-Kollman scheme [216,217]. ESP and MerzKollman are synonyms for MK . CHelp

Produce charges fit to the electrostatic potential at points selected according to the CHelp scheme [218]. CHelpG

Produce to the electrostatic potential at points selected according to the CHelpG charges scheme fit [219]. Dipole

When fitting charges to the potential, constrain them to reproduce the dipole moment. ESPDipole is a synonym for Dipole. AtomDipole

When fitting charges to the potential, also fit a point dipole at each atomic center. ReadRadii

Read radiiof(in Angstroms) element for useby in afitting Theseinarealternative read as pairs atomic symbolfor andeach radius, terminated blankpotentials. line. ReadAtRadii

Read in alternative radii (in Angstroms) for each atom for use in fitting potentials. These are read as pairs of atom number and radius, terminated by a blank line. NBO-RELATED OPTIONS


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NBO

Requests a full Natural Bond Orbital analysis, using NBO version 3 [12,13,14,15,16,17,18,19]. NCS

Requests partitioning of thebonds NMRand shielding tensors (computed using GIAOs)Shielding into magnetic acontributions from lone pairs using the Natural Chemical Analysis of Bohmann et. al. [ J.A. Bohmann, F. Weinhold and T.C. Farrar, J. Chem. Phys. 107 (1997) 1173.], which is based upon the NBO analysis method. By default, an analysis of the isotropic shielding is performed. NoNCS skips this analysis. NCSDiag

Requests an NCS analysis of the diagonal tensor elements. NCSAll

Requests an NCS analysis of all tensor components. NPA

Requests just the Natural Population Analysis phase of NBO. NBORead

Requests a full NBO analysis, with input controlling the analysis read from the input stream. Use this option to specify keywords for NBO. Refer to the NBO documentation for details on this input. NBODel

Requests NBO analysis of the effects of deletion of some interactions. Only possible with SCF methods. Implies will be2read; refer the NBO for details. Note that NBOthat inputNBO startsinput in column so that thetoUNIX shelldocumentation does not interpret the initial $. SaveNBOs

Save natural bond orbitals in the checkpoint file (for later visualization). SaveNLMOs

Save natural localized molecular orbitals in the checkpoint file (for later visualization). SaveMixed

Savecheckpoint the NBOsfile for (for the occupied orbitals and the NLMOs for the unoccupied orbitals in the later visualization).

Density, Output=WFN


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The following input file requests a bond order analysis using NBO 5: # B3LYP/6-31G(d,p) Pop=NBORead Example of NBO bond orders 0

1

C H C H H

0.000000 0.919278 -0.919239 0.000000 -0.919278 0.919239

0.665676 1.237739 1.237787 -0.665676 -1.237739 -1.237787

0.000000 0.000000 0.000000 0.000000 0.000000 0.000000

$nbo bndidx $end

Pressure Specifies the pressure to be used for thermochemistry analysis (in atmospheres). The value should be specified as an option: # ... Pressure=1.5

The default is 1 atmosphere.

Prop This properties keyword tells Gaussian to compute electrostatic properties [276,278,377,555]. By default, the potential, electric field, and electric field gradient at each nucleus are computed. The density used for the electrostatic analysis is controlled by the Density keyword. PROPERTY SELECTION OPTIONS EFG

Specifies that potential, field and field gradient are to be computed. This is the default.


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Potential

Specifies that the potential but not the field or field gradient are to be computed. NoPotential suppresses computation of the electric potential and higher properties. Field

Specifies that the potential and field, but not the field gradient, are to be computed. EPR

Compute the anisotropic hyperfine coupling constants (i.e., spin-dipole EPR terms) [276,278,377]. INPUT SOURCE-RELATED OPTIONS

If both Read and Opt are specified, the order of the input sections is fixed points (Read), then optimized points (Opt). Read

Causes the program to read a list of additional centers at which properties will be computed from the input stream. The Cartesian coordinates of each center in angstroms are read in free field, with one center per line, in the standard orientation. Opt

Causes the program to read a list of centers as in Prop=Read, but then to locate the minimum in the electric potential closest to each specified point. FitCharge

Fit atomic charges to the electrostatic potential at the Van der Waals surface. Dipole

Constrain fitted charges to the dipole moment. Grid

Specifies that the potential is to be calculated at one or more grids of points and written to an external file (generally superseded by cubegen). This option requests mapping of the electric potential over a 2D grid of points. The points can be specified as a uniform rectangular grid, as an arbitrary collection read from an auxiliary file (both described below), or via the input format used by Cube=Potential (see Appendix D). Three additional input lines are required for a uniform grid: KTape,XO,YO,ZO N1,X1,Y1,Z1 N2,X2,Y2,Z2

Fortran unit for write, coords. of map's lower left corner. # grid rows & vertical step size. # grid column & horizontal step size.

For points read from an auxiliary file, a single line of input supplies all of the necessary information:


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N,NEFG,LTape,KTape

The coordinates of N points in Angstroms will be read from unit LTape, in format 3F20.12. LTape defaults to 52. The potential ( NEFG=3), potential and field ( NEFG=2), or potential, field, and field gradient ( NEFG=1) will be computed and written to unit KTape . For example, indicates 19,696 fortotheFortran electrostatic potential (code 3) willthe be following read from input Fortran unit 10,that with outputpoints written unit 11: 19696,3,10,11

HF, all DFT methods, CIS, MP2, MP3, MP4(SDQ), CID, CISD, CCD, CCSD and QCISD.

Density, cubegen

Pseudo

This keyword requests that a model potential be substituted for the core electrons. The Cards option is by far its most-used mode. Gaussian supports a new effective core potential (ECP) input format (similar to that used by ExtraBasis) which is described below. When reading-in pseudopotentials, do not give them the same names as any internally-stored pseudopotentials: CEP, CHF, LANL1, LANL2, LP-31, SDD and SHC. If used the ONIOM, the Pseudo keyword applies to all layer of the ONIOM. If you want to read in ECPs only for one ONIOM layer, then use the GenECP keyword instead.

Read

Read pseudo-potential data from the input stream. Input is described in the next subsection below. Cards is a synonym for Read. Old

Read pseudo-potential data using the old format (used by Gaussian 92 and earlier versions).


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CHF

Requests the Coreless Hartree-Fock potentials. This option is normally used with the LP31G basis sets. SHC

Requests the SHC potentials. LANL1

Requests the LANL1 potentials. LANL2

Requests the LANL2 potentials. FULL ECP INPUT FORMAT

Effective Core Potential operators are sums of products of polynomial radial functions, Gaussian radial functions and angular momentum projection operators. ECP input a therefore specifies which potential to use on each atomic center, and then includes collection of triplets of: (coefficient, power of R, exponent) for each potential for each term in each angular momentum of the ECP. Since only the first few angular momentum components have different terms, the potential is expressed as (1) terms for the general case, typically d or f and higher projection, and (2) the extra terms for each special angular momentum. Thus for an LP-31G potential, which includes special s and p projected terms, the input includes the general (d and higher) term, the s-d term (i.e., what to add to the general term to make the s component) and the p-d term. All ECP input is free-format. Each block is introduced by a line containing the center numbers (from the molecule specification) and/or atomic symbols, specifying the atoms and/or atoms types to which it applies (just as for general basis set input-see the discussion of the Gen keyword). The list ends with a value of 0. The pseudo-potential for those centers/atoms follows: Name,Max,ICore

Name of the potential, maximum angular momentum of the potential (i.e., 2 if there are special s and projections, 3 if there are s, p, and d projections), anda previous number ofpotential, core electrons replaced by the potential. If Name matches the name of that potential is reused and no further input other than the terminator line (see below) is required. For each component ( I=1 to Max) of the current potential, a group of terms is read, containing the following information:


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Title

A description of the block, not otherwise used. NTerm

Number of terms in the block. NPower,Expon,Coef

Power of R, exponent, and coefficient for each of the NTerm terms. NPower includes the R 2 Jacobian factor. An example of an input file which includes a nonstandard ECP with its associated basis set is given below. SIMPLIFIED ECP INPUT FORMAT

Gaussian adds flexibility to ECP input by allowing it to include pre-defined basis sets

names. An ECP definition maycase, be replaced a line the containing standard keyword for a pre-defined basis set. In this the ECPsbywithin specifiedthebasis set corresponding to the specified atom type(s) will be used for that atom (see the examples). KEYWORDS FOR STUTTGART/DRESDEN ECP INPUT

In Pseudo input, keywords for these ECP's are of the form XYn where n is the number of core electrons which are replaced by the pseudopotential and X denotes the reference system used for generating the pseudopotential (S for a single-valence-electron ion or M for a neutral atom). Y specifies the theoretical level of the reference data: HF for Hartree-Fock, WB for

Wood-Boring quasi-relativistic and DF for Dirac-Fock relativistic. For one- or twovalence electron atoms SDF is a good choice; otherwise MWB or MDF is recommended (although for small atoms or for the consideration of relativistic effects, the corresponding SHF and MHF pseudopotentials may be useful).

Energies through f functions only, and gradients through d functions only. The Stuttgart/Dresden ECPs are not uniformly available the periodic following table shows the availability of the various XY across combinations, alongtable. with The valid values for n. The Defaults columns list the equivalencies for the SDD keyword (which selects an all electron basis set through Cl and ECPs thereafter) and when IOp(3/6) is set to 6 (which selects ECPs for all elements). Valid values of n for given values of X and Y


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Atom

Defaults IOp(3/6=6)

MWB

SDF

SHF

MDF

MHF

SDD keyword D95 D95

1 2

H He

3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K

SDF2 SDF2 MWB2 MWB2 MWB2 MWB2 MWB2 MWB2 SDF10 SDF10 MWB10 MWB10 MWB10 MWB10 MWB10 MWB10 MWB10

D95 D95 D95 D95 D95 D95 D95 D95 6-31G 6-31G D95 D95 D95 D95 D95 6-31G MWB10

20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se

MWB10 MDF10 MDF10 MDF10 MDF10 MDF10 MDF10 MDF10 MDF10 MDF10 MDF10 MWB28 MWB28 MWB28 MWB28

MWB10 MDF10 MDF10 MDF10 MDF10 MDF10 MDF10 MDF10 MDF10 MDF10 MDF10 MWB28 MWB28 MWB28 MWB28


2 2 2 2 2 2

10 10 10 10 10 10 10 10

2 2 2 2 2 2 2 10 10 10 10 10 10 10 10 18

18

18

18

28 28 28 28 28 28

28 28 28 28 28

10 10 10 10 10 10 10 10 10 10

MDF10 MDF10 MDF10 MDF10 MDF10 MDF10 MDF10 MDF10 MDF10 MDF10

28

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35 36 37 38

Br Kr Rb Sr

MWB28 MWB28 MWB28 MWB28


28 28 28 28

39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55

Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs

MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB46 MWB46 MWB46 MWB46 MWB46 MWB46


28 28 28 28 28 28 28 28 28 28 46 46 46 46 46 46 46

56 57 58 59 60 61 62 63 64 65 66 67 68 69 70

Ba La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb

MWB46 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28

MWB46 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28 MWB28

46 54 28,46,47 28,47,48 28,48,49 28,49,50 28,50,51 28,51,52 28,52,53 28,53,54 28,54,55 28,55,56 28,56,57 28,57,58 28,58,59 28,59


28 28 36 36

36 36 28 28 28 28 28 28 28 28 28 28

46 46 46 46 46 46

46 46

54

54 46,47 47,48 48,49 49,50 50,51 51,52 52,53 53,54 54,55 55,56 56,57 57,58 58,59 59

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71 72 73 74

Lu Hf Ta W



28,60 60 60 60

60 60 60 60

75 76 77 78 79 80 81 82 83 84 85 86 89 90 91 92 93

Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Ac Th Pa U Np



60 60 60 60 60 60,78 78 78 78 78 78 78 60 60 60 60 60

60 60 60 60 60 60,78 78 78 78 78 78 78 60 60 60 60 60

94 95 96 97 98 99 100 101 102 103 104

Pu Am Cm Bk Cf Es Fm Md No Lr Rf

MWB60 MWB60 MWB60 MWB60 MWB60 MWB60 MWB60 MWB60 MWB60 MWB60

MWB60 MWB60 MWB60 MWB60 MWB60 MWB60 MWB60 MWB60 MWB60 MWB60

60 60 60 60 60 60 60 60 60 60

78

60 60

60 60 60 60 60 60 60 60 60 60 92

Note: These ECPs are not available for elements 87 (Fr), 88 (Ra), and 105 and higher


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ChkBasis, ExtraBasis, Gen, GenECP

Specifying an ECP. This input file runs an RHF/LP-31G calculation on hydrogen

peroxide, with the basis set and ECP data read from the input file: # HF/Gen Pseudo=Read Test Hydrogen peroxide 0,1 O H,1,R2 O,1,R3,2,A3 H,3,R2,1,A3,2,180.,0 R2=0.96 R3=1.48 A3=109.47 General basis set input

**** O 0

ECPs for

the oxygen atoms.

OLP 2 2

ECP name=OLP, applies to d & higher,

replaces 2 electrons.

D component

Description for the

general terms.

3

Number of

terms to follow.

1 1 80.0000000 30.0000000 -1.60000000 -0.40000000 2 1.0953760 -0.06623814 S-D projection angular momentum). 3 0 0.9212952 0.39552179 0 28.6481971 2.51654843 2 9.3033500 17.04478500 P-D angular momentum). 2 2 52.3427019 27.97790770 2 30.7220233 -16.49630500 block for oxygen.

Corrections for projected terms (lowest

Corrections for projected terms (highest

Blank line indicates end of the ECP

The basis set data follows the molecule specification section. The first line of the ECP data requests that a potential be read in (type 7) for atoms number 1 and 3 (the oxygen atoms) and that no potential is to be used for atoms 2 and 4 (the hydrogen atoms). The second line of ECP data begins the input for the first center requiring a read-in potential, in this case oxygen atom 1. The potential on this center is named OLP, it is a


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general term and applies to angular momentum 2 (D) and higher, and the potential replaces two electrons. Next comes a title for the general term, the number of components of that term, and each of the components, followed by the corrections for the projected terms, lowest angular momentum first. Finally, the next potential, for center 3 in this case, consists of a single line. It uses the same name as a previous potential (that of center 1) and soand the number information already read must in is reused. that the maximum angular moment of core electrons still be Note specified, even though they will generally be the same for all uses of a given potential. Using Standard Basis Set Keywords to Specify ECPs . The following input file

illustrates the use of the simplified ECP input format: # Becke3LYP/Gen Pseudo=Read Opt Test HF/6-31G(d) Opt of Cr(CO)6 0 1 Cr 0.0 specification 0.0 0.0 continues ... molecule C O 0 6-31G(d) **** Cr 0 LANL2DZ **** Cr 0 LANL2DZ

ECP for chromium atom. Use the ECP in this basis set.

Punch This output specification keyword allows the user to "punch"-in more modern parlance, send to a separate output file-useful information at various points in the calculation. The output is disposed of in whatever manner is usual for Fortran alternate-unit output under the appropriate operating system (for example, unit 7 is sent to the file fort.7 under UNIX.) Options are used to specify what information should be output. All of these options can be combined, except that only one of MO and NaturalOrbitals can be requested. Note, however, that they are distinct and non-interacting. For example, Punch(MO, Gamess) sends both the molecular orbital and Gamess input information to the file; it does not format the MO information in Gamess input format.


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Archive

Requests that a summary of the important results of the calculation be punched. This output is in the same format used by the Browse Quantum Chemistry Database System. Title

Punches the title section. Coord

Punches the atomic numbers and Cartesian coordinates in a form which could be read back into Gaussian. Derivatives

Punches the energy, Cartesian nuclear coordinate derivatives, and second derivatives in format 6F12.8, suitable for later use with Opt=FCCards. MO

Punches the orbitals in a format suitable for Guess=Cards input. NaturalOrbitals

Punches natural orbitals (for the density selected with the Density keyword). HondoInput

Punches an input deck for one version of Hondo, which is probably easily modified to fit most others. GAMESSInput

Punches an input deck for GAMESS. All

Punches everything except natural orbitals.

Output

QCISD This method keyword requests a Quadratic CI calculation [72], including single and double substitutions. Note that this keyword requests only QCISD and does not include the triples correction [556,557] by default (see T below).


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T

Requests a Quadratic CI calculation including single and double substitutions with a triples contribution to the energy added [72]. E4T

Requests a Quadratic single andofdouble substitutions with a triples contribution to CI thecalculation energy andincluding also an evaluation MP4 triples. Must be specified with the T option. TQ

Requests a Quadratic CI calculation including single and double substitutions with an energy contribution from triples and quadruples [64] added. T1Diag

Computes the Q1 diagnostic of T. J. Lee and coworkers [423,558]. Note that Q1 is analogous to the T1 diagnostic for CCSD when it is computed using QCISD instead of the Coupled Cluster method. FC

The frozen-core options for defining inner-shells to be excluded from the correlation calculation are valid with this keyword. See the discussion here for details. Conver= N


Specifies the maximum number of cycles. The default is 50.

Analytic energies and gradients for QCISD, numerical gradients for QCISD(T), and numerical frequencies for all methods.

CCSD

The predicted energy from a QCISD calculation appears in the output in the final QCISD iteration: DE(CORR)=

-.54999890D-01

E(CORR)=


-.7501966245D+02

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When QCISD(T) is specified, the preceding output is followed by the energy including the non-iterative triples contribution: QCISD(T)= -.75019725718D+02

ReArchive This calculation type keyword requests that the information on the checkpoint file be used to generate an archive entry. In this case, no new calculation is performed.

Archive, Test

SAC-CI

The keyword selects the Symmetry Adapted Cluster/Configuration Interaction (SAC-CI) methods of Nakatsuji and coworkers [121,122,123,124,125,126,127,128,129,130,131,132,133,134,135]. For detailed information on this method, consult the SAC-CI documentation available at the following web site: www.sbchem.kyoto-u.ac.jp/nakatsuji-lab. SAC-CI jobs must specify a reference state for the subsequent excited states calculations. For closed shell systems, the default RHF wavefunction used by SAC-CI is appropriate. For open shell ground states, you must either select an ROHF ground state wavefunction by including ROHF in the route section in addition to SAC-CI, or you must specify a closed shell state for the ground state calculation using the AddElectron or SubElectron option. See the examples for more information. SPIN STATE OPTION Singlet=( suboptions)

Specifies that singlet states are to be calculated. The parenthesized list of suboptions specifies the desired states and other calculation parameters. Other spin state selection options are CationDoublet (Doublet is a synonym), AnionDoublet, Triplet, Quartet, Quintet, Sextet and Septet. More than one spin state may be specified.


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SPIN STATE SUBOPTIONS SpinState=(NState=(i1,i2,...))

Sets the number of states of the specified type to be calculated for the various irreducible representations the molecule's point (e.g., group.8 Up maysobeon). specified, depending on theofmolecular symmetry for to D2height , 4 forvalues C2v, and The shorthand form NState= N specifies a value of N for each irreducible representation. Degeneracies are handled by assuming the closest linear symmetry (e.g., D2 for Td). SpinState=(Density)

Calculate unrelaxed density matrices and perform Mulliken population analysis for all computed SAC-CI states of spin SpinState. See the examples for more information. SpinState=(SpinDensity)

Calculate spin density matrices for all computed SAC-CI states of spin SpinState. Implies the FullActive option as well. SpinState=(NoTransitionDensity )

By default, the transition density and oscillator strength are calculated between the SAC ground state and the SAC-CI singlet excited states when SpinState is Singlet , and between the lowest SAC-CI states and SAC-CI excited states for other spin states. NoTransitionDensity disables these calculations for the corresponding spin state. OTHER COMMONLY-USED OPTIONS TargetState=(SpinState= s, Symmetry=m, Root=n)

Specifies the target state for a geometry optimization or a gradient calculation, or for use with the Density keyword. S is the keyword indicating its spin multiplicity (i.e., Singlet, Doublet, etc.), m is the irreducible representation number of its point group, and n is the solution number in the desired spin state (determined by a previous energy calculation). AddElectron

Add one electron to the open shell reference SCF configuration. This is the default for such systems for CationDoublet , Doublet, Quartet and Sextet. SubElectron

Subtract one electron from the open shell reference SCF configuration. This is the default for such systems for AnionDoublet . TransitionFrom=(SpinState= s, Symmetry=m, Root=n)


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Specifies the initial state for for calculating transition density matrices. S is the keyword indicating its spin multiplicity (i.e., Singlet, Doublet, etc.), m is the irreducible representation number of its point group, and n is the solution number in the desired spin state (as for TargetState above). AllProperties

Calculate multipole moments through hexadecapole, all N th moment to the 4th moment, all electrostatic properties and the diamagnetic terms (shielding and susceptibility). This option applies to all spin states which specify the Density suboption. NoProperty

Don't calculate any molecular properties. SelectCISOnly

Terminate the calculation after the CIS initial guess has been calculated. You can use this option to determine the state number of a particular state in which you are interested (e.g., for TargetState). See the examples for an alternative method. SACOnly

Performs only the calculation for the reference state and does not compute any excited states. ADDITIONAL OPTIONS FOR EXPERT USERS ADDITIONAL SPIN STATE SUBOPTIONS

SpinState=(MaxR= N )

Set the maximum excitation level to N . SpinState=(NonVariational)

Solve the SAC-CI equations for non-symmetric matrices. Variational proceeds by diagonalizing symmetrized matrices, and it is the default. Note that this option only applies to the excited state portion of the calculation (the ground state calculation always uses a nonvariational procedure). SpinState=(InCoreDiag)

Force use of the in-core algorithm. SpinState=(Iterative=item)

Force the use of an iterative algorithm. Item specifies the initial guess type: SInitial for CIS and SDInitial for CISD.


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PROCEDURAL OPTIONS FC

The frozen-core options for defining inner-shells to be excluded from the correlation calculation are valid with this keyword. In general, the size of the active space greatly affects the accuracy of isSAC-CI calculations. For this reason, using full orbital window is recommended. the default for geometry optimizations andagradient calculations. Full LMO=type Use the specified type of localized MO as types are PM (Pipek-Mezey) and Boys.

reference orbitals. The available

MacroIteration= N

Requests the use of N macroiterations within an optimization step. The default value of N is 0. InCoreSAC

For solution of the SAC equations using the in-core algorithm. MaxItDiag= N

Set the maximum number of diagonalization iterations. MaxItSAC= N

Set the maximum number of iterations for solving the SAC equations. DConvDiag=M

Set the diagonalization energy convergence criteria to 10-M. DConvSAC=M

Set the energy convergence criteria to 10-M when solving the SAC equations. ACCURACY LEVEL OPTIONS

SD-R

Perform the calculation using singles and doubles linked excitation operators. This is the default. General-R

Perform the calculation including linked excitation operators through sextuples. LevelOne

Set the threshholds for selection of the double excitation operators to the lowest recommended level. LevelThree is the most accurate level, and it is the default. LevelTwo is intermediate in accuracy between the other two levels. WithoutDegeneracy


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By default, perturbation selection is performed so that degeneracies are retained. This option suppresses this test, resulting in reduced computational requirements. Use of this option is not recommended for production use. NoLinkedSelection

Disables perturbation selection threshholds for linked operators (i.e., all operators are included). NoUnlinkedSelection

Disables perturbation selection threshholds for unlinked operators (i.e., all operators are included). FullUnlinked

Include all types of unlinked terms. Forces the use of the in-core algorithm. In order to include all terms, all three of these preceding options are required, currently at a considerable performance penalty. WithoutR2S2

Ignore R2S2 unlinked integrals. This option results in a tradeoff between decreased accuracy and computational requirements. EgOp

Generate quadruple and higher-order linked operators in the General-R scheme via the exponential generation algorithm. This is the default for single point energy calculations. MaxR option (up to a maximum of The highest orderselection excitation level is specified viathe theLevelOne 6). Perturbation threshholds are set via , LevelTwo and LevelThree options. FullRGeneration

Generate all higher-order linked operators in the General-R scheme up to MaxR =4 and then perform perturbation selection as above. This is the default for gradient calculations and geometry optimizations. GROUP SUM OPERATION OPTIONS

These options are used to ensure all pointsmust in multipoint calculation types like potential energy surfaceconsistency scans. Thebetween Scan calculation be performed three times: at the first point with BeforeGSUM, then at some or all subsequent points with CalcGSUM and then finally at all points with AfterGSUM. The actual results are provided by the final calculation. This procedure is only valid for singlet, triplet, ionized and electron-attached states, and it is not compatible with the General-R option.


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BeforeGSUM

Initialize a series of linked calculations. Use this option in a calculation at the first point. CalcGSUM

Collect data and determine the threshholds and operator selections at specified points in order to form a consistent set which can then be used at every point. AfterGSUM

Perform SAC-CI calculations at each point using the GSUM data collected previously with the CalcGSUM option. MEMORY USE OPTIONS

These options can be used to increase the program default settings after a failed job has indicated that a resource shortfall was the problem. MaxR2Op= N

Set the maximum number of R2 operators after perturbation selection to N . The default is 100,000. MaxEgOp= N

Set the maximum number of operators in the General-R method to N . The default is 5,000.

Analytic energies and optimizations and numerical frequencies. Geometry optimizations default to using a full window. Specifying a different frozen core option for an optimization will result in numerical gradient calculations and correspondingly poorer performance.

Density

If you want to locate the lowest two singlet excited states, you could use a route like the following: # SAC-CI=(Full,Singlet=(NState=8))/6-31G(d) NoSymm ...

This will search for 8 singlet states, ignoring symmetry. The two lowest excited states will probably be among those found by the calculation.


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Alternatively, you could use the following route: # SAC-CI=(Full,Singlet=(NState=4))/6-31G(d) ...

This calculation will locate the lowest four singlet excited states for each irreducible representation. To specify the desired number of singlet excited states for each irreducible representation for a molecule with C2v symmetry, use a route like this one: # SAC-CI=(Full, Singlet=(2,2,1,2))/6-31G(d) ...

Locating States with an Inexpensive Initial Calculation . You can use a preliminary,

lower-accuracy calculation in order to locate a desired excited state at reduced computational cost. For example, the following route will locate 4 singlet excited states of each symmetry type: # SAC-CI=(Full,Singlet=(NState=4),LevelOne)/6-31G(d) ...

This job could be followed by a normal (LevelThree) calculation for the state(s) of interest. For example: # SAC-CI=(Full,Singlet=(1,0,1,0))/6-31G(d) ...

Calculations on Open Shell Systems. To predict excited states for vinyl radical, a

neutral doublet radical, you could use a route like the following: # ROHF/6-31G(d) SAC-CI=(Full,Doublet=(NState=3),Quartet=(NState=3)) ...

This specifies the use of an ROHF wavefunction for the ground state, and it computes three doublet and three quartet excited states for each irreducible representation. You could use a similar approach for the triplet ground state of methylene. Geometry Optimizations. To optimize a specific excited state, use the TargetState

option: # Opt SAC-CI=(Singlet=(Nstate=4), TargetState=(SpinState=Singlet,Symmetry=1,Root=2))/6-31G(d) ...

Computinganalysis Densities Molecular Properties. To compute thethis unrelaxed population forand all predicted excited states, use a route like one: density and # SAC-CI=(Full,Singlet=(...,Density),Triplet=( ...,Density))/631G(d) ...

If you wanted to compute the unrelaxed density and population analysis only for the triplet states, then you would omit the Density suboption to the Singlet option.


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To compute the relaxed density and population analysis for only one specified state, use a route like the following: # SAC-CI=(Full,Singlet=(NState=4),TargetState=(...)) Density=Current ...

Note that this job will be much more computationally expensive than the previous one as it requires a full gradient calculation. SAC-CI Output. SAC-CI calculations produce a table like the following for each

requested spin state (this example is for singlet states): --------------------------------------------------------------------Transition dipole moment of singlet state from SAC ground state --------------------------------------------------------------------Symmetry Sol Excitation Transition dipole moment (au) Osc. energy (eV) X Y Z strength --------------------------------------------------------------------A1 0 0.0 Excitations are from this state. A1 1 8.7019 0.0000 0.0000 0.4645 0.0460 A1 2 18.9280 0.0000 0.0000 -0.4502 0.0940 A1 3 18.0422 0.0000 0.0000 -0.8904 0.3505 A1 4 18.5153 0.0000 0.0000 0.0077 0.0000 A2 1 7.1159 0.0000 0.0000 0.0000 0.0000 A2 2 18.2740 0.0000 0.0000 0.0000 0.0000 B1 1 1.0334 -0.2989 0.0000 0.0000 0.0023 B1 2 18.7395 -0.6670 0.0000 0.0000 0.2042 B1 3 22.1915 -0.1500 0.0000 0.0000 0.0122 B1 4 15.8155 0.8252 0.0000 0.0000 0.2639 B2 1 11.0581 0.0000 0.7853 0.0000 0.1671 B2 2 15.6587 0.0000 1.5055 0.0000 0.8696 B2 3 24.6714 0.0000 -0.7764 0.0000 0.3644 B2 4 23.5135 0.0000 -0.1099 0.0000 0.0070 ---------------------------------------------------------------------

Note that the various excited states are grouped by symmetry type—and not in order of increasing energy—in the output.

Scale Specifies the frequency scale factor to be used for thermochemistry analysis. The value should be specified as an option: # ... Scale=0.95

The default is 1.0 except for compound methods where the default specified by the method is used.


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Scan This calculation type keyword requests that a potential energy surface (PES) scan be done. A rigid PES scan is performed, which consists of single point energy evaluations over a rectangular grid involving selected internal coordinates. The molecular structure must be defined using Z-matrix coordinates. The number of steps and step size for each variable are specified on the variable definition lines, following the variable's initial value. For example: R1 1.41 3 0.05 A1 104.5 2 1.0 A2 120.0

R1done This input variable to beforstepped 3 times by 0.05. Thusvariables. four, R1Similarly, values (1.41, 1.46, 1.51, causes and 1.56) will be each combination of other 3 values for A1 will be used, and A2 will be held fixed at 2.2. All in all, a total of 12 energy evaluations will be performed. Any number of variables can be stepped. The units of the step-sizes are controlled by the Units keyword and default to Angstroms and degrees.

A relaxed PES scan (with geometry optimization at each point) is requested with the Opt keyword. If any scanning variable breaks symmetry during the calculation, then you must include NoSymm in the route section of the job, or the job will fail with an error.

Restart

Restarts a PES scan calculation. A failed Scan calculation may be restarted from its checkpoint file by simply repeating the route section of the original job, adding the Restart option to the Scan keyword. No other input is required.

Opt

Output files from PES scans conclude with a table summarizing the results for the job: Scan completed.


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Summary of the N R ---- --------1 0.9600 2 1.0100 3 1.0600 4 0.9600 5 1.0100 6 1.0600 7 0.9600 8 1.0100 9 1.0600 10 0.9600 11 1.0100 12 1.0600 ---- ---------

potential surface scan: A HF --------- ----------104.5000 -38.39041 104.5000 -38.41306 104.5000 -38.42336 105.5000 -38.39172 105.5000 -38.41430 105.5000 -38.42453 106.5000 -38.39296 106.5000 -38.41547 106.5000 -38.42564 107.5000 -38.39412 107.5000 -38.41657 107.5000 -38.42668 --------- -----------

Chapter 8 of Exploring Chemistry with Electronic Structure Methods [308] provides a detailed discussion of potential energy surface scans.

SCF

This keyword controls the functioning of the SCF procedure. Options are used to specify the desired behavior, alternate algorithms, and so on. Click here for more information on maximizing performance in the SCF for different problems. Single point direct SCF calculations are run with modest convergence criteria automatically in the interest of speed. The default for this case is sufficient for 0.1 kcal mole-1 accuracy in the SCF energy and 3 decimal places in the density matrix-sufficient for population analysis, electrostatic potential derived charges, and the like. SCF=Tight requests full convergence for this case. SCF and DFT single point energy calculations involving basis sets which include diffuse functions should always use the SCF=Tight keyword to request tight SCF convergence criteria. At the other extreme, sometimes it is convergence useful to startcriteria off optimizations lesstheaccurate integral, SCF, and CPHF cutoffs and and then towith enable more accurate and expensive limits only when the geometry has stabilized. The Sleazy option reduces all of these cutoff values. It also turns off archiving. The default SCF procedure uses a combination of EDIIS [559] and CDIIS, with no damping or Fermi broadening.


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Single point energy calculations involving basis sets which include diffuse functions should always use the SCF=Tight keyword to request tight SCF convergence criteria. See reference [560] for a discussion of SCF convergence and stability. ALGORITHM SELECTION OPTIONS DIIS DIIS calls for and NoDIIS prohibits use of Pulay's Direct Inversion in the Iterative

Subspace extrapolation method [561]. CDIIS

Use only CDIIS. CDIIS implies Damp as well. Fermi

Requests temperature broadening during early iterations [562], combined with CDIIS and NoFermi suppresses Fermi broadening and is the default. Fermi implies damping. Damp as well by default, and also include level shifting. Damp

Turn on dynamic damping of early SCF iterations. NoDamp is the default. However, damping is enabled if SCF=Fermi or SCF=CDIIS is requested. Note that damping and EDIIS do not work well together. NDamp= N

Allow dynamic damping for up to N SCF iterations (the default is 10). QC

Calls for the use of a quadratically convergent SCF procedure [563]. By default this involves linear searches when far from convergence and Newton-Raphson steps when close (unless the energy goes up). This method is slower than regular SCF with DIIS extrapolation but is more reliable. SCF=QC is not available for restricted open shell (RO) calculations. XQC

Add an extra SCF=QC step in case first-order SCF has not converged. MaxConventionalCycles= N

Sets the limit on conventional SCF cycles during SCF=XQC to N . SD

Does steepest descent SCF. SSD

Does scaled steepest descent SCF.


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DM

Calls for use of the direct minimization SCF program [564]. It is usually inferior to SCF=QC and retained for backwards compatibility and as a last resort. Available only for RHF closed shell and UHF open shell calculations. VShift[= N ]

Shift orbital energies by N *0.001 (i.e., N millihartrees); N defaults to 100. This option disables automatic archiving. N =-1 disables level shifting; NoVShift is equivalent to this setting. MaxCycle= N

Changes the maximum number of SCF cycles permitted to N ; the default is 64 (or 512 for SCF=DM and SCF=QC). Note that with DIIS turned on, memory requirements increase with increasing maximum number of cycles. FullLinear

Specifies By thatdefault, L508 (SCF=QC , SD, or SSD ) should linear microiteration searches at eachcaused iteration. a full minimization is done onlydoif full the initial the energy to go up. MaxRot= N

Set the maximum rotation gradient for a Newton-Raphson step in SCF=QC to 10-N. Above this, scaled steepest descent is used, above 100 times this, steepest descent is used. The default value for N is 2. FinalIteration FinalIteration

performs and NoFinalIteration prevents a final non-extrapolated, non-

incremental iteration. after an SCF using DIIS or a direct SCF has converged. The default is NoFinalIteration IncFock

Forces use of incremental Fock matrix formation. This is the default for direct SCF. NoIncFock prevents the use of incremental Fock matrix formation, and it is the default for conventional SCF. Pass

For in-core calculations, saves the integrals on disk as well, to avoid recomputing them in Link 1002. Only useful for frequency jobs in conjunction with SCF=InCore. NoPass forces integrals to be recomputed during each in-core phase. TightLinEq

Use tight convergence in linear equation solution throughout SCF=QC. By default, the convergence criterion is tightened up as the rotation gradient is reduced. VeryTightLinEq

Use even tighter convergence in the linear equation solutions (microiterations)


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throughout the QCSCF. This option is sometimes needed for nearly linearly-dependant cases. VTL is a synonym for VeryTightLinEq. INTEGRAL STORAGE OPTIONS Direct

Requests a direct SCF calculation, in which the two-electron integrals are recomputed as needed. This is the default SCF procedure in Gaussian. This is possible for all available methods, except for MCSCF second derivatives and anything using complex orbitals. Note that for single-point direct SCF calculations, a loose convergence criterion (10-4) is used in the interest of speed. InCore

Insists that the SCF be performed storing the full integral list in memory. This is done automatically in a direct SCF calculation if sufficient memory is available. SCF=InCore is available to force in-core storage or abort the job if not enough is available. NoInCore prohibits the use of the in-core procedure, for both the SCF and CPHF. Conventional

The two-electron integrals are stored on disk and read-in each SCF iteration. NoDirect is a synonym for Conventional.

Conver= N

Sets the SCF convergence criterion to 10-N. This is a density-based convergence criterion except for GVB and CASSCF, for which it is in terms of the orbital change and energy change, respectively. VarAcc

Use modest integral accuracy early in direct SCF, switching to full accuracy later on. The default for direct SCF, can be turned off via NoVarAcc. VarInt is a synonym for VarAcc, and NoVarInt is a synonym for NoVarAcc. Tight

Use normal, tight convergence in the SCF. The default for everything except CASSCF and direct SCF single points. Synonymous with NoSinglePoint , NoSP, NoSleazy and TightIntegrals . SinglePoint

Requests the loose SCF convergence criteria appropriate for single points; equivalent to SCF=(Conv=4,VarInt,NoFinal,Direct) . The default for single point CASSCF or direct SCF. Can be abbreviated SP. Sleazy is a synonym for SinglePoint . VerySleazy

Reduce cutoffs even further; uses Int=CoarseGrid and single-point integral accuracy


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during iterations, followed by a single iteration with the usual single point grid (MediumGrid). Not recommended for production quality calculations. SYMMETRY-RELATED OPTIONS IDSymm

Symmetrize the density matrix at the first iteration to match the symmetry of the molecule ("initial density symmetrize"). NoIDSymm is the default. DSymm

Symmetrize the density matrix at every SCF iteration to match the symmetry of the molecule ("density symmetrize"). NoDSymm is the default. DSymm implies IDSymm. NoSymm

Requests that all orbital symmetry constraints be lifted. It is synonymous with Guess=NoSymm and Symm=NoSCF. Symm

Retain all symmetry constraints: make the number of occupied orbitals of each symmetry type (abelian irreducible representation) match that of the initial guess. Use this option to retain a specific state of the wavefunction throughout the calculation. It is the default only for GVB calculations. IntRep

Calls for the SCF procedure to account for integral symmetry by replicating the integrals using the symmetry operations. Allows use of a short integral list even if the wavefunction does not have the full molecular symmetry. Available for L502 (the default for RHF, ROHF and UHF) and L508 (SCF=QC). FockSymm

Calls for the SCF procedure to account for integral symmetry (use of the "petite" integral list) by symmetrizing the Fock matrices. This is the default. FSymm is a synonym for FockSymm

RESTART-RELATED OPTIONS Save

Save the wavefunction on the checkpoint file every iteration, so the SCF can be restarted. This is the default for direct SCF. NoSave suppresses saving the wavefunction. Restart

Restart the SCF from the checkpoint file. SCF=DM cannot be restarted.

SCRF


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This keyword requests that a calculation be performed in the presence of a solvent, using one of the following models: •

•

• •

The Onsager model [281,282,283,284,565,566], which places the solute in a spherical cavity within the solvent reaction field. Polarizable Continuum (PCM) models in which the cavity is created via a series of overlapping spheres, initially devised by Tomasi and coworkers [285,286,287,288,289,290,291,292,293,295]. The current implementation is the work of Barone and coworkers [285,286,287,297,299,300,301,302,303] and Tomasi, Mennucci and coworkers [293,294,296,298]. A static isodensity surface polarized continuum model (IPCM) [307]. A Self-Consistent Isodensity PCM (SCI-PCM) model [307].

Gaussian 03 can also carry out a PCM calculation using Klamt's form of the conductor

reaction field (COSMO) [567] and generate the input data for the COSMO-RS solubility programs. See the discussion of the COSMORS keyword for details. COSMO-RS is distributed as COSMOtherm by COSMOlogic GmbH, www.cosmologic.de. REQUIRED AND OPTIONAL INPUT: PCM MODELS

Keywords and options specifying details for a PCM calculation (SCRF=PCM, CPCM or IEFPCM) may be specified in an additional blank-line terminated input section provided that the Read option is also specified. Keywords within this section follow general Gaussian input rules. The available keywords are listed in a separate subsection following the examples. REQUIRED INPUT: ONSAGER MODEL

For the Onsager model (SCRF=Dipole), the solute radius in Angstroms and the dielectric constant of the solvent are read as two free-format real numbers on one line from the input stream. A suitable solute radius is computed by a gas-phase molecular volume calculation (in a separate job step); see the discussion of the Volume keyword. REQUIRED INPUT: IPCM AND SCI-PCM MODELS

For the IPCM and SCI-PCM models, the input consists of a line specifying the dielectric constant of the solvent and an optional isodensity value (the default for the latter is 0.0004). OPTION FOR SPECIFYING THE SOLVENT Solvent=item

Selects the solvent in which the calculation is to be performed. Note that the solvent may


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also be specified in the input stream in various ways for the different SCRF methods. If unspecified, the solvent defaults to water. Item is a solvent name chosen from the following list: • • • • • • • • • • • • • • • • • • • • • • • • •

Water or H2O: ε=78.39 Acetonitrile or CH3CN: ε=36.64 DiMethylSulfoxide or DMSO: ε=46.7 Methanol or CH3OH: ε=32.63 Ethanol or CH3CH2OH: ε=24.55 Isoquinoline : ε=10.43 Quinoline: ε=9.03 Chloroform or CHCl3: ε=4.9 Ether or DiEthylEther or CH3CH2OCH2CH3: ε=4.335 DiChloroMethane or MethyleneChloride or CH2Cl2: ε=8.93 DiChloroEthane or CH2ClCH2Cl: ε=10.36 CarbonTetrachloride or CCl4: ε=2.228 Benzene C6H6: ε=2.247 or C6H5CH3 : ε=2.379 Toluene or ChloroBenzene or C6H4Cl: ε=5.621 NitroMethane or CH3NO2: ε=38.2 Heptane or C7H16: ε=1.92 CycloHexane or C6H12: ε=2.023 Aniline or C5H5NH2: ε=6.89 Acetone or CH3COCH3: ε=20.7 TetraHydroFuran or THF: ε=7.58 DiMethylSulfoxide or DMSO or CH3SOCH3: ε=46.7 Argon or Ar: ε=1.43 Krypton : ε=1.519 : ε=1.706 Xenon or or XeKr

We list the ε values here for convenience, but be aware it is only one of many internal parameters used to define solvents. Thus, simply changing the ε value will not define a new solvent properly. METHOD SELECTION OPTIONS PCM

For quantum mechanical calculations, performs a reaction field calculation using the IEF Note that of this has and PCM model [288,290,293] (see below). This is98. theAlso, default. some details theoption formalism changed in meaning with respect to Gaussian the implementation have changed, as described in [302]. IEFPCM

Perform a PCM calculation using the integral equation formalism model [288,293,294,295]. The model of Chipman [568] is closely related to this earlier one [569].


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Note that if IEF-PCM is used for an anisotropic or ionic solvent, then items in the PCM input section must be used to select the anisotropic and ionic dielectric models for these types of solvents, using the Read option (see below). CPCM

Perform a PCM calculation using the CPCM polarizable conductor calculation model [292,303]. COSMO

Perform a PCM calculation using the CPCM model with Klamt's radii and iterative solution. Dipole

Perform an Onsager model reaction field calculation. IPCM

Perform an IPCM model reaction field calculation. Isodensity is a synonym for IPCM. SCIPCM

Perform an SCI-PCM model reaction field calculation: perform an SCRF calculation using a cavity determined self-consistently from an isodensity surface. COSMORS

Requests a conductor PCM calculation (CPCM) using atomic radii and other parameters as suggested by Klamt for his models. The name of the text file to write with input data for COSMO-RS is read from the input stream, after the geometry, basis set and other data. Structures may be optimized with SCRF=COSMO prior to COSMORS single point calculations. DIPOLE MODEL OPTIONS A0=val

Sets the value for the solute radius in the route section (rather than reading it from the input stream). If this option is included, then Solvent or Dielectric must also be included. Dielectric= val

Sets the value for the dielectric constant of the solvent. This option overrides Solvent if both are specified. PCM MODELS OPTION Read

Indicates that a separate section of keywords and options providing calculation parameters should be read from the input stream (as described above).


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Modify

Pick up SCRF information from the checkpoint file, but also read modifications from the input stream. IPCM MODEL OPTIONS GradVne

Use Vne basins for the numerical integration. GradRho

Use density basins for the numerical integration. The job may fail if non-nuclear attractors are present. SCI-PCM MODEL OPTIONS UseDensity

Force the use of the density matrix in evaluating the density. UseMOs

Force the use of MOs in evaluating the density. GasCavity

Use the gas phase isodensity surface to define the cavity rather than solving for the surface self-consistently. This is mainly a debugging option.

The PCM models are available for semi-empirical, HF, DFT, MP2, MP3, MP4(SDQ), QCISD, CCD, CCSD, CASSCF, CIS, TD, CID and CISD energies and HF, DFT, MP2, CIS and CASSCF gradients. IEFPCM and PCM may be used to compute frequencies for the methods listed for gradients. Int=AM1

must be used in the route section if SCRF AM1 is specified.

The solvent reaction field for PCM MP2 calculations is equilibrated to the solute electronic density obtained at the SCF level. Note that ΔGsolvation=EPCM-MP2 –EMP2 cannot be obtained using the PCM SCFVac option, but must be obtained by comparing the results of two separate calculations, performed in gas-phase and in solvent. CIS PCM [298] and TD PCM [300] calculations are by default non-equilibrium calculations with respect to the polarization process between the solvent reaction field and the charge density of the electronic state indicated in the input (where the ground state is the default). However, equilibrium CIS PCM calculations are the default for geometry optimizations.


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By default, CASSCF PCM [297] calculations corresponds to an equilibrium calculation with respect to the solvent reaction field- solute electronic density polarization process. Calculation of non equilibrium solute-solvent interaction involving two different electronic states (e.g. the initial and final states of a vertical transition) can be performed using the NonEq=type PCM keyword, in two separate job steps (see the PCM input section below). The IPCM model is available for HF, DFT, MP2, MP3, MP4(SDQ), QCISD, CCD, CCSD, CID, and CISD energies only. The SCI-PCM model is available for HF and DFT energies and optimizations and numerical frequencies. The Onsager model is available for HF, DFT, MP2, MP3, MP4(SDQ), QCISD, CCD, CCSD, CID, and CISD energies, and for HF and DFT optimizations and frequency calculations. The Opt Freq keyword combination may not be used in SCRF=Onsager calculations. Only single-point calculations are possible with COSMORS option. These calculations will typically be done as single-point solvated calculations using SCRF=PCM optimized geometries. SCRF=PCM and SCRF=IPCM jobs can be restarted from the read-write file by using the Restart keyword in the job's route section. SCRF=SCIPCM calculations which fail during the SCF iterations should be restarted via the SCF=Restart keyword.

Volume, SCF

PCM Energy. Energy output from the SCRF models other than Onsager appears in the

normal way within the output file, followed by additional information about the calculation. For example, here is the section of the output file containing the predicted energy from a PCM calculation: SCF Done:

E(RHF) = -98.569083211 A.U. after 5 cycles Convg = 0.4249D-05 -V/T = 2.0033 S**2 = 0.0000 -------------------------------------------------------------------Variational PCM results ======================= (a.u.) = -98.568013 (a.u.) = -98.573228 Total free energy in solution:


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with all non electrostatic terms (a.u.) = -98.569083 -------------------------------------------------------------------(Polarized solute)-Solvent (kcal/mol) = -3.27 -------------------------------------------------------------------Cavitation energy (kcal/mol) = 5.34 Dispersion energy (kcal/mol) = -3.08 Repulsion energy (kcal/mol) = 0.34 Total non electrostatic (kcal/mol) = 2.60 --------------------------------------------------------------------

Additional output lines may appear when various PCM options are included. The total energy in solution is the sum of the SCF energy and all of the non-electrostatic energy terms (both are highlighted in the output). Note that the PCM results also include the dipole moment in the gas phase and in solution (not shown here), and the various components of the predicted SCRF energy. For all iterative SCRF methods, note that the energy to use is the one preceding the Convergence achieved message (i.e., the one from the final iteration of the SCRF method). Onsager Energy. The energy computed by an Onsager SCRF calculation appears in the

output file as follows: Total energy (include solvent energy) =

-74.95061789532

COSMO/RS Example. Here is a sample input file: # B3LYP/6-311+G(2d,2p) SCF=(Tight) SCRF=COSMORS Water generating COSMO-RS input 0 1 o h,1,r h,1,r,2,a r .96 a 104.5 water.cosmo

This job will produce the data file water.cosmo. Additional Keywords for PCM Calculations

Additional input keywords may be specified for PCM SCRF calculations. They are placed in a separate input section, as in this example: # HF/6-31++G(d,p) SCF=Tight SCRF=(PCM,Read,Solvent=Cyclohexane) Test

PCM SP calculation on hydrogen fluoride


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0,1 H F 1 R R=0.9161 TABS=300.0 ALPHA=1.21 TSNUM=70

This Gaussian job performs a PCM energy calculation on the molecule HF using the solvent cyclohexane. The calculation is performed at a temperature of 300 K using a scaling factor for all atoms except acidic hydrogens of 1.21 and a value of 70 tesserae per sphere. The final input section ends as usual with a blank line. The following keywords are available for controlling PCM calculations (arranged in groups of related items): SPECIFYING THE SOLVENT

The solvent for the PCM calculation may be specified using the normal Solvent option to the SCRF keyword. The solvent name keyword or ID number may also be placed within the PCM input section. Alternatively, the EPS and RSOLV keywords may be used in the PCM input section to define a solvent explicitly: EPS=e

Dielectric constant of the solvent. RSOLV=radius

Solvent radius in Angstroms. DENSITY=val

Density of the solvent EPSINF=val

Optional value for the dielectric constant at infinite frequency. Note that if any of these parameters are specified, the others default to the values for water, and so you will probably want to set all of them appropriately. CALCULATION METHOD VARIATIONS NODIS

Skip the calculation of dispersion solute-solvent interaction energy. NOREP

Skip the calculation of repulsion solute-solvent interaction energy.


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NOCAV

Skip the calculation of the cavitation energy. By default, non-electrostatic energy contributions are computed and printed, but they are not added into the energy and its derivatives during geometry optimizations. The DDis, DRep, and DCav may be used to include them for the rare cases where keywords the non-electrostatic energy terms are known to affect the geometry. Such cases will require care during optimization, and the optimization process may be trickier and more lengthy. SCFVAC

Performs the gas phase calculation before that in solution. It allows for the calculation of ΔGsolvation, the variation of the dipole moment in solution and so on, but only by HF or DFT methods. NOSCFVAC is the default. The recommended radii for this calculation type are the United Atom Topological Model applied on radii optimized for the HF/631G(d) level of theory (specified with RADII=UAHF ). FITPOT

Performs analysis of the solute solvent interaction energy in terms of atomic or atomic groups additive contributions. This analysis involves a fitting of atomic charges to the molecular electrostatic potential in solution. FIXGRD

Compute the electrostatic energy gradients neglecting the geometrical contributions (i.e. at "fixed cavity"). MobGrd is the default. FIXHSS

Compute the electrostatic second derivatives neglecting the geometrical contributions (i.e. at "fixedenergy cavity"). MobHss is the default. ITERATIVE

Solve the PCM electrostatic problem to calculate polarization charges through a linear scaling iterative method using a Jacobi-like scheme. This is the default for COSMO-RS. INVERSION

Solve the PCM electrostatic problem to calculate polarization charges through an inversion matrix algorithm. This is the default, except for COSMO-RS. MXITER= Specify the N maximum number of iterations allowed to the iterative solution of the

electrostatic problem. 200 is the default. QCONV=type |N

Set the convergence threshold for the iterative calculations of the PCM polarization charges to 10-N or to one of the following predefined types: VeryTight (10-12), Tight (10-


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9

) and Sleazy (10-6). Default convergence values are QConv=Tight for PCM energy calculation and QCONV =VeryTight for PCM energy gradients calculations. NODIIS

Skip the DIIS algorithm for the iterative solution of the PCM problem when the Jacobi scheme is exploited. MxDIIS= N

Number of vectors used in the DIIS extrapolation NoFMM

Turn off the use of the Fast Multipole Method in the iterative solution. FMM is the default. LMax= N

Set the degree of the polynomial for the electrostatic potential multipole expansion in the FMM. 6 is the default. BoxLen= N Set the length in Angstroms of the FMM box. 6.0 is the default. PRECOND= N

Set the preconditioner type for the PCM iterative solution. 0 means no preconditioner. 1 corresponds to a simple Jacobi preconditioner, while 2 is a preconditioner based on the correlation considered only for charges located on the same sphere. 2 is the default. BiCGS DIIS option is not Set the iterative a stabilized biconjugate allowed with thisalgorithm keyword,toand the algorithm defaultsgradient to JacobiThe when it is used. CGS

Set the iterative algorithm to a squared conjugate gradient. This is the default for CPCM calculations. CG

Set the iterative algorithm to a conjugate gradient. The ICOMP keyword, formerly used to specify the charge compensation mode, is no longer needed and is deprecated. ANISOTROPIC AND IONIC SOLVENTS ANISOTROPIC

Performs a PCM calculation for anisotropic solvent according to the IEF-PCM formalism. The 3-rank symmetric tensor representing the dielectric constant must be


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specified as the values for these six additional keywords: EPSX, EPSY, EPSZ, EUPHI, EUTHE, and EUPSI (all of them take a parameter: e.g., EPSX=value). IONIC

Performs a PCM calculation for ionic solution according to the IEF-PCM formalism. The 3

2

ionic strength in mol/dm Å has to be specified as the value to the keyword DISM. SPECIFYING THE MOLECULAR CAVITY

By default, the program builds up the cavity using the United Atom (UA0) model, i.e. by putting a sphere around each solute heavy atom: hydrogen atoms are enclosed in the sphere of the atom to which they are bonded. There are three UA models available (see below). The cavity can be extensively modified in the PCM input section: putting spheres around specified hydrogens, changing sphere parameters and the general cavity topology, adding extra spheres to default, and so on. The whole molecular cavity can be also provided bythe thecavity user inbuilt the by input section. RADII=model

Indicates the topological model and/or the set of atomic radii used. Available models and sets are: UA0: Use the United Atom Topological Model applied on atomic radii of the UFF force

field. UAHF: Use the United Atom Topological Model applied on radii optimized for the

HF/6-31G(d) level of theory. These are the recommended radii for for the calculation of ΔGsolvation via the PCM keyword. SCFVAC UAKS: Use the United Atom Topological Model applied on radii optimized for the

PBE0/6-31G(d) level of theory. UFF: Use radii from the UFF force field. Hydrogens have individual spheres (explicit

hydrogens). PAULING: Use the Pauling (actually Merz-Kollman) atomic radii (explicit hydrogens). BONDI: Use the Bondi's atomic radii (explicit hydrogens).

KLAMT : Use atomic radii from the COSMO method. This is the default when SCRF=CosmoRS is used. SPHEREONH= N When using the UA0 model, places an individual sphere on the hydrogen at the N th

position in the atoms list.


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SPHEREONACIDICH

When using the UA0 model, put individual spheres on acidic hydrogens (those bonded to N, O, S, P, Cl and F atoms). ALPHA= scale

Specify the electrostatic scaling factor by which the sphere radius is multiplied. The default value is 1.2. SURFACE=type

Specify the type of molecular surface representing the solute-solvent boundary. Available options are: SES: Solvent Excluding Surface. The surface is generated by the atomic or group spheres

and by the spheres created automatically to smooth the surface ("added spheres"). This is the default for electrostatic contribution. VDW: Van der Waals surface. Uses unscaled atomic radii and skip the generation of

"added spheres" to smooth the surface. SAS: Solvent Accessible Surface. The radius of the solvent is added to the unscaled radii

of atoms and/or atomic groups. NOADDSPH

Avoid the generation of added spheres to smooth the cavity surface. ADDSPH is the default. MODIFYSPH

Alter parameters for one or more spheres. The modified spheres can be indicated in the PCM input using the following format: ModifySph

atom_number radius [alpha]

EXTRASPH= N

Add N user-defined spheres to the cavity. Parameters of the spheres can be indicated using the following format: ExtraSph=N

X Y Z radius [alpha] orientation.

X,Y,Z are the Cartesian coords. in the standard

NSPH= N

The cavity is built just from the N spheres provided by the user, specified on lines of the following format:


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atom_number radius [alpha] X Y Z radius [alpha] orientation.

X,Y,Z are the Cartesian coords. in the standard

NOSYMMCAV

Do not impose the molecular symmetry to the cavity. SymmCav is the default. OFAC=value

Specify the overlap index between two interlocking spheres [570]. Decreasing this index results in a smaller number of added spheres. The default value is 0.89. RMIN=value

Set the minimum radius in Angstroms for SES added spheres. Increasing this value results in a smaller number of added spheres. The default value is 0.2. TSARE=area

Set the average area of the tesserae generated on each sphere in the cavity surface, in units of Å2 (area=0.2 is the default value). Reducing this value results in a finer surface discretization. Values suggested as the best compromise between accuracy and numerical stability range between 0.2 and 0.4, or even larger for molecular mechanics calculations. SMALLTESSERA=value

Threshold to discard small tesserae (the default is 10-4 Å2). SHORTEDGE=value

Threshold to discard short edges in a tessera (the default is 5.0*10-7 Angstroms). OUTPUT OPTIONS GEOMVIEW

Create the file tesserae.off describing the cavity. This files contains input for the GeomView program (see geomview.org ) which can be used to visualize the molecular cavity. PCMDOC

Include the descriptions and values of all the internal PCM parameters in the Gaussian log file.

SP


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This calculation type keyword requests a single-point energy calculation. It is the default when no calculation type keyword is specified.

All methods.

See the discussion of the methods keywords for examples of their energy output formats.

Sparse Use sparse matrix storage for performance enhancement of large calculations (above around 400 atoms) [34]. The keyword's option allows you to specify the cutoff value for considering matrix elements to be zero.

Loose

Sets the cutoff to 5 * 10-5. Medium

Sets the cutoff to 5 * 10-7. This is the default for semi-empirical methods. Tight

Sets the cutoff to 1 * 10-10. This is the default for DFT methods. N

Sets the cutoff to 1 * 10-N.

Energies and gradients andmore DFTthan methods (closedThis shell calculations). It is usefulforforAM1, AM1Hartree-Fock calculations of 200 atoms. keyword may also be used within method specifications for ONIOM layers.

FMM


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Stable This calculation type method requests that the stability of the Hartree-Fock or DFT wavefunction be tested. Gaussian has the ability to test the stability of a singledeterminant wavefunction with respect to relaxing various constraints [106,107] (see also [560]). These include: • • •

Allowing an RHF determinant to become UHF. Allowing orbitals to become complex. Reducing the symmetry of the orbitals.

The default is to test for all instabilities but not to re-optimize the wavefunction. If Stable=Opt is specified, by default the wavefunction is allowed to be unrestricted if necessary. In examining the results prior to a frequency calculation, it suffices to see if any singlet instabilities exist for restricted wavefunctions or if any instabilities (singlet or triplet) exist for unrestricted wavefunctions. In examining the results prior to a MøllerPlesset calculation, an internal instability only affects the validity of the results if the pairs of orbitals mixed are of the same spatial symmetry. The validity of restricted Møller-Plesset energies based on wavefunctions which are unstable with respect to becoming UHF is also questionable [571]. The Stable keyword causes the program to compute a wavefunction as usual and then to determine if the resulting determinant is a local minimum with the specified degrees of freedom taken into consideration. Note that analytic frequency calculations are only valid if the wavefunction has no internal instabilities, and Møller-Plesset calculations are only valid if the wavefunction has no internal instabilities within the constrained symmetry. By default, only real instabilities (i.e., not complex) are sought. The code which checks for a complex stability (Link 902) is older and less reliable and should not be used unless complex orbitals are of interest. GENERAL OPTIONS RExt

Test for external real instability as well as internal instability (the default). Int Test for internal instability (a lower determinant with

the same constraints) only.

RRHF

Constrain the wavefunction testing or reoptimization to be real, spin-restricted. Synonymous with Singlet.


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RUHF

Constrain the wavefunction testing or reoptimization to be real, spin-unrestricted. Synonymous with Triplet. CRHF

Allow testing for real to complex instabilities in spin-restricted wavefunctions. CUHF

Allow testing for real to complex instabilities in spin-unrestricted wavefunctions. WAVEFUNCTION REOPTIMIZATION OPTIONS Opt

If an instability is found, reoptimize the wavefunction with the appropriate reduction in constraints, repeating stability tests and reoptimizations until a stable wavefunction is found. RepOpt is a synonym for Opt. NoOpt prevents reoptimization and is the default. 1Opt

Redo the SCF once if an instability is detected. ALGORITHM-RELATED OPTIONS Direct

Forces a direct calculation (the default). MO

Forces a stability calculation using transformed two-electron integrals (i.e., in the MO basis). AO

Forces a calculation using the AO integrals (written to disk), avoiding an integral transformation. The AO basis is seldom an optimal choice, except for small molecules on systems having very limited disk. It is the default when SCF=Conven is also specified. InCore

Forces an in-core algorithm. ICDiag

Forces in-core full diagonalization of the matrix formed in memory from transformed integrals. It implies the use of MO integrals. Restart

Restarts the calculation off the checkpoint file. Also implies SCF=Restart.


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HF and DFT methods.

SCF

Symmetry This keyword specifies the uses of molecular symmetry within the calculation. If symmetry is in use, the molecule may be rotated to a different coordinate system, called the standard orientation, before the calculation is performed. Derivatives are then rotated back to the original (input ) orientation. Orbitals are printed in the standard orientation, and input for properties and background charge distributions is required in the standard orientation. The NoSymmetry keyword prevents the reorientation and causes all computations to be performed in the Z-matrix orientation. By default, symmetry is used wherever possible to reduce CPU, disk storage, and I/O requirements. Symmetry use can be completely disabled by NoSymm, or modified by the Symm keyword and one or more options.

Int Int enables and NoInt disables use of integral symmetry (use of the "petite list"). Synonymous with Int=[No]Symm. Grad NoGrad disables and Grad enables use of symmetry in integral derivative evaluation. SCF NoSCF disables and SCF enables use of N3 symmetry in SCF, which is used by default only for GVB calculations. SCF=NoSCF is equivalent to Guess=LowSym and

combining all irreducible representations together. Loose

Tells the program to use looser cutoffs in determining symmetry at the first point. It is designed for use with suboptimal input geometries. Tight says to use the regular criteria at the first point, and it is the default. Follow

Try to follow point group/orientation during optimization.


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PG= group

Use no more symmetry than that found in the specified point group. Axis=[X|Y|Z]

Specify axis to help specify subgroup. On

Turn on symmetry when it would otherwise be off, such as with massage. This can cause wrong answers, so it should only be used if you know what you're doing!

Int, SCF

TD This method keyword requests an excited state energy calculation using the timedependent Hartree-Fock or DFT method [109,110,111]. Note that the normalization criteria used is =1. Electronic circular dichroism (ECD) analysis is also performed during these calculations [255,256,257,258,259,260]

Singlets

Solve only for singlet excited states. Only effective for closed-shell systems, for which it is the default. Triplets

Solve only for triplet excited states. Only effective for closed-shell systems. 50-50

Solve for half triplet and half singlet states. Only effective for closed-shell systems. Root= N

Specifies the state of interest. The default is the first excited state ( N =1). NStates=M

Solve for M states (the default is 3). If 50-50 is requested, NStates gives the number of each type of state for which to solve (i.e., the default is 3 singlets and 3 triplets).


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Add= N

Read converged states off the checkpoint file and solve for an additional N states. This option implies Read as well. Read

Reads initial for guesses for the checkpoint file. Note initial guess one basis setstates cannotoffbethe used for a different one.that, unlike for SCF, an EqSolv

Whether to perform equilibrium or non-equilibrium PCM solvation. NonEqSolv is the default. IVOGuess

Force use of IVO guess. This is the default for TD Hartree-Fock. NoIVOGuess forces the use of canonical single excitations for guess, and it is the default for TD-DFT. The HFIVOGuess option forces the use of Hartree-Fock IVOs for the guess, even for TDDFT. SOS Do sum-over states polarizabilities, etc. By default, all excited states are solved for. A list of frequencies at which to do the sums is read in. Zero frequency is always done and need not be in the list.

Energies using Hartree-Fock or a DFT method. Optimizations are available using numerical gradients.

CIS, ZINDO, Output

Here is the key part of the output from a TD excited states calculation: Excitation energies and oscillator strengths: Excited State 1: Singlet-A2 4.1280 eV 300.35 nm f=0.0000 8 -> 9 0.68197 This state for optimization and/or second-order correction. Copying the excited state density for this state as the 1-particle RhoCI density. Excited State 2: 8 -> 10

Singlet-B2 0.70318

6.4912 eV


191.00 nm

f=0.0356

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Excited State 3: 8 -> 11

Singlet-A1 0.70219

7.4378 eV

166.69 nm

f=0.0541

The results on each state are summarized, including the spin and spatial symmetry, the excitation energy, the oscillator strength, and (on the second line for each state) the largest coefficients in the CI expansion. The ECD results appear in the output as follows: <0|del|b> * (Au), Rotatory Strengths (R) in cgs (10**-40 erg-esu-cm/Gauss) state X Y Z R(velocity) 1 0.0045 -0.0007 -0.0001 5.6444 2 -0.0040 -0.0004 0.0018 -2.9442 3 -0.0007 -0.0024 0.0043 1.3201 <0|r|b> * (Au), Rotatory Strengths (R) in cgs (10**-40 erg-esu-cm/Gauss) state X Y Z R(length) 1 2 3

-0.0300 0.0193 0.0034

0.0048 0.0017 0.0111

0.0007 -0.0083 -0.0200

5.7826 -3.0068 1.3067

Temperature Specifies the temperature to be used for thermochemistry analysis (in Kelvin). The value should be specified as an option: # ... Temperature=300

The default is 298.15 K.

Test This keyword suppresses the automatic creation of an archive entry (formerly intended Archive, which is for Browse Chemistry System).from Its antonym is log the the default. NoteQuantum that archive entries Database may be extracted Gaussian files after the fact using the pluck utility.

Archive, Rearchive


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TestMO The cutoffs used in computing and storing integrals and the convergence criteria applied in SCF and CPHF calculations are appropriate for most molecules and basis sets. However, if a nearly linearly dependent basis set is used, very large MO coefficients may occur and in combination with the finite accuracy of other terms lead to substantial numerical errors. By default CPHF and post-SCF calculations are aborted if any MO coefficient is larger than 1000. (Note that this corresponds to a coefficient of 1012 for the contribution of an AO integral to an MO integral involving four virtual orbitals.) The NoTestMO keyword suppresses this check. It should be used only after careful thought. TestMO is the default.

TrackIO This keyword requests routine-by-routine statistics of I/O and CPU usage.

#P

Transformation This keyword controls the algorithm used for integral transformation, as well as the types of transformed integrals produced. INTEGRAL TRANSFORMATION ALGORITHM OPTIONS Direct

Requests that the direct transformation routines be used. Equivalent to L804. Link 804 will select between the in-core, fully direct, and semi-direct methods automatically. This is the default. InCore

Forces use of the in-core algorithm in Link 804


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FullDirect

Forces use of the fully direct (MO integrals in core) method in Link 804. SemiDirect

Forces use of the semi-direct algorithm in Link 804. Conventional

Requests that the original transformation method based on externally stored integrals be used. This was the only choice in Gaussian 90 and earlier versions. NoDirect is a synonym for Conventional. Old2PDM

Forces the old-fashioned process of the 2PDM in post-SCF gradients (sorted in L1111 and then processed in L702 and L703). This is slow, but it reduces memory requirements. This option cannot be used for frozen-core calculations. New2PDM

Causes the 2PDM to be generated, used, and discarded by L1111 in post-SCF gradient calculations. This is the default and fastest method, and it must be used for frozen-core calculations. INTEGRAL SELECTION OPTIONS Full

Forces a transformation over all orbitals (i.e., including transformed integrals involving all virtuals). ABCD is a synonym for Full. IJAB

Produce only integrals. IAJB

Produce and integrals. IJKL

Produce , , and integrals. IJKA

Produce , , , and integrals. IABC

Produce , , , , and integrals.

Molecular Mechanics Methods


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There are three molecular mechanics methods available in Gaussian. They were implemented for use in ONIOM calculations, but they are also available as independent methods. No basis set keyword should be specified with these keywords. The following force fields are available: AMBER : The AMBER force field as described in [37]. The actual parameters







Terminology: Gaussian contains built-in parameter sets for the built-in force fields listed

above; theseinare to as hard-wired parameters. parameters are reading ones specified by the user thereferred input stream for the current job (or a Soft previous job when parameters from the checkpoint file). By default, when no relevant option is given, the hard-wired parameters are the only ones used. HardFirst

Read additional parameters from the input stream, with hard-wired parameters having priority over the read-in, soft ones. Hence, read-in parameters are used only if there is no


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corresponding hard-wired value. Note that wildcards matches within the hardwared parameter set take precidence over soft parameters, even when the latter contains an exact match for the same item. Use SoftFirst if you want to override hard-wired parameter matches. SoftFirst






Since parameters can betospecified it is default possibleisfor more if than oneare any parameter specification match ausing givenwildcards, structure. The to abort there ambiguities in the force field. The following options specify other ways of dealing with multiple matches. FirstEquiv


found. LastEquiv





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O-O--0.5




ONIOM, Geom=Connect


Unless otherwise indicated, distances are in Angstroms, angles are in degrees, energies are in Kcal/mol and charges are in atomic units. Function equivalencies to those found in standard force fields are indicated in parentheses. In equations, R refers to distances and θ refers to angles. Wildcards may be used in any function definition. They are indicated by a 0 or an asterisk. In MM force fields, the non-bonded (Vanderwaals and electrostatic) interactions are evaluated for every possible pair of atoms. However, interactions between pairs of atoms that are separated by three bonds or less are usually scaled down (in most force fields, using a factor 0.0 for pairs separated by one or two bonds, and some value between 0.0 and 1.0 for pairs that are separated by three bonds). There are a number of ways to implement the calculation of non-bonded interactions. We follow a two-step procedure. First, we calculate the interactions between all pairs, without taking the scaling into account. In this step, we can use computationally efficient (linear scaling) algorithms. In the second step, we subtract out the contributions that should have been scaled, but were included in the first step. Since this involves only pairs that are close to each other based on the connectivity, the computer time for this step scales again linearly with the size of the system. Although at first sight it seems that too much work is done, the overall algorithm is the more efficient than the alternatives.


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In the soft force field input, the NBDir function entry corresponds to the calculation of all the pairs, and the NBTerm entry is used for the subsequent subtraction of the individual pairs. However, to make things easier, you can specify just the non-bonded master function NonBon, which is automatically expanded into the actual functions NBDir and NBTerm during pre-processing. Vanderwaals parameters, used for NBDir and NBTerm (See MMFF94 below for MMFF94-type Vanderwaals parameters). VDW Bond-length Well-depth






0 1 2 3 4

No Vanderwaals Arithmetic (as for Dreiding) Geometric (as for UFF) Arithmetic (as for Amber) MMFF94-type Vanderwaals C-Type is the Coulomb type: 0 No Coulomb 1 1/R 2 1/R 2 3 1/R buffered (MMFF94)


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V-Cutoff and C-Cutoff are the Vanderwaals and Coulomb cutoffs (respectively):

0 No cutoff >0 Hard cutoff <0 Soft cutoff VScale1-3 are Vanderwaals factors for 1 topairs. 3 bond pairs. CScale1-3 are Coulomb scale factors for 1 scale to 3 bond separated If separated any scale factor < 0.0, the 1/1.2

scaling is used (as for Amber). Coulomb and Vanderwaals direct (evaluated for all atom pairs). NBDir V-Type C-Type V-Cutoff C-Cutoff







Step down table Table Original-atom-type Stepping-down-type(s).

Harmonic stretch I (Amber [1]): ForceC *(R- Req)2


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HrmStr1 Atom-type1 Atom-type2 ForceC Req





BO Bond order (if <0, it is determined on-the-fly) PropC Proportionality constant Ri and R j are atomic bond radii defined with AtRad. X i and X j are GMP electronegativity

values defined with EleNeg. Z i and Z j are the effective atomic charges defined with EffChg.





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Harmonic bend (Amber [1]): ForceC *(T-θeq)2 HrmBnd1 Atom-type1 Atom-type2 Atom-type3 ForceC θeq 2

ForceC Force constant θeq Equilibrium angle (in kcal/(mol*rad )







with EffChg.



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Mag 4 NPaths PO1-PO4 Phase offsets Mag 1...Mag 4 V/2 magnitudes NPaths Number of paths (if < 0, determined on-the-fly).

Dreiding torsion (Dreiding [13]): V *[1-cos( Period *(θ- PO))]/(2* NPaths)


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DreiTrs Atom-type1 Atom-type2 Atom-type3 Atom-type4 V PO Period NPaths

V Barrier height V PO Phase offset Period Periodicity NPaths

Number of paths (if < 0, determined on-the-fly).


Period Periodicity PO Phase offset V Barrier height V NPaths

Number of paths. When zero or less, determined on-the-fly.






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•

•







Harmonic Wilson angle (MMFF94 [6]): ( ForceC /2)*(θ2) summed over all three Wilson angles θ.


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HrmWil Atom-type1 Atom-type2 Atom-type3 Atom-type4 ForceC


Stretch-bend I (MMFF94 [5]): ( ForceC1*(R 12- Req12)+ ForceC2*(R 32- Req23))*(θ-θeq) StrBnd1 Atom-type1 Atom-type2 Atom-type3 ForceC1 ForceC2 Req 12 Req23 θeq ForceC1, ForceC2 Force constants (in md/rad) Req12, Req23 Equilibrium bond lengths θeq Equilibrium angle USING SUBSTRUCTURES


-1 -2 -3



-1 -2 -3

0 ≤ θ ≤ 45 45 < θ ≤ 135 135 < θ ≤ 180


-i-n


For dihedral angles, one or two substructures may be used (e.g., AmbTrs-1-2). Use a zero for the first substructure to specify only the second substructure. First substructure : • • • •

-0 -1 -2 -3

Skip this substructure (substructure "wildcard") Single central bond: 0.00 ≤ bond order < 1.50 Double central bond: 1.50 ≤ bond order < 2.50 Triple central bond: bond order ≥ 2.50


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Second substructure: • • •

-i-1 -i-2 -i-3



H_ C_2 C_2 * * *

C_2 360.0 1.08 C_2 350.0 1.50 C_2 500.0 1.40 C_2 * 50.0 120.0 C_2 C_2 * 5.0 180.0 C_2 C_2 * 45.0 180.0

2.0 -1.0 2.0 -1.0

Units The Units keyword controls the units used in the Z-matrix for distances and angles and related values, such as step-sizes in numerical differentiation. The defaults are Angstroms and degrees.

Ang

Distances are in Angstroms (this is the default). AU

Distances are in atomic units (Bohrs). Deg

Angles are in degrees (the default). Rad

Angles are in radians. RESTRICTIONS

The Charge, Cube and Massage keywords are not affected by the setting of the Units keyword, and their input is always interpreted in units of Angstroms and degrees.


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Volume This keyword requests that the molecular volume be computed, defined as the volume inside a contour of 0.001 electrons/bohr 3 density. The density to be used can be specified with the Density keyword. Since a Monte-Carlo integration is done, the computed volume is only accurate to about two significant figures, but this is sufficient to estimate a radius for use with the Onsager solvent reaction field model. The recommended radius (which is 0.5Å larger than the radius corresponding to the computed volume) is printed in the output. Since other, more accurate solvent models are available in Gaussian 03, this keyword has applicability only in preparation for frequency calculations using SCRF=Dipole.

Tight

Requests an increased density of points for more accurate integration. By default, the volume is computed to an accuracy of about 10%. Use of this option is recommended if the computed molecular volume is needed more quantitatively.

Hartree-Fock, all DFT methods, CIS, MP2, MP3, MP4(SDQ), CID, CISD, CCD, CCSD and QCISD.

SCRF=Dipole

W1U W1BD These method keywords request two variations of the W1 method of Martin [94,95]. The first, selected with the W1U keyword, is the W1U method. This is the W1 method modified to use UCCSD instead of ROCCSD for open shell systems. W1BD requests a related method which substitutes BD for coupled cluster [96]. This method is both more expensive and more accurate than CBS-QB3 and G3.


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You should specify alternative isotopes for W1 jobs using the standard method. However, the ReadIsotopes option is retained for rerunning completed calculations under different conditions.

ReadIsotopes

Specify alternate temperature, pressure, and/or isotopes (the defaults are 298.15 K, 1 atmosphere, and the most abundant isotopes). This information appears in a separate input section having the format: temp pressure [scale] isotope mass for atom 1 isotope mass for atom 2 ... isotope mass for atom n


where temp, pressure, and scale are the desired temperature, pressure, and an optional scale factor for frequency data when used for thermochemical analysis (the default value defined by the specified method is used if scale is omitted or set to 0.0); these values must be real numbers. The remaining lines hold the isotope masses for the various atoms in the molecule, arranged in the same order as they appeared in the molecule specification section. If integers are used to specify the atomic masses, the program will automatically use the corresponding actual exact mass (e.g., 18 specifies O18, and Gaussian uses the value 17.99916). Restart

Restart an incomplete W1 calculation.

Calculation Summary Output. After all of the output for the component job steps,

Gaussian prints a table of results for these methods. Here is the key part of the output

from a W1U calculation: W1 Electronic Energy Temperature= 298.150000 E(ZPE)= 0.020965 W1 (0 K)= W1 Enthalpy=

-76.462067 -76.458287

-76.483031 Pressure= 1.000000 E(Thermal)= 0.023800 W1 W1

Energy= -76.459231 Free Energy= -76.479709

The predicted energy is given followed by values for the thermochemistry analysis.

ZINDO


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This method keyword requests an excited state energy calculation using the ZINDO/S method [112,113,114,115,116,117,118,119,120]. Note that ZINDO calculations must not specify a basis set keyword. By default, a ZINDO calculation is performed using the ten highest occupied orbitals and the ten lowest virtual orbitals. Use the Window option to define a different orbital set.

Singlets

Solve only for singlet excited states. Only effective for closed-shell systems, for which it is the default. Triplets Solve only for triplet excited

states. Only effective for closed-shell systems.

50-50

Solve for half triplet and half singlet states. Only effective for closed-shell systems. Root= N

Specifies the "state of interest." The default is the first excited state ( N =1). NStates=M

Solve for M states (the default is 3). If 50-50 is requested, NStates gives the number of each type of state for which to solve (i.e., the default is 3 singlets and 3 triplets). Add= N

Read converged states off the checkpoint file and solve for an additional N states. Window=(m[,n])

The two values specify the starting and ending orbitals to be used. A value of zero indicates the first or last orbital, depending on where it is used. If the value for the first orbital is negative (-m), then the highest m orbitals are retained; the value for the last orbital is negative (-n), then the highest n orbitals are frozen. If m is positive and n is omitted, n defaults to 0. If m is negative and n is omitted, then the highest | m| occupied and lowest |m| virtual orbitals are retained.

Energies only. The Density keyword is ignored for ZINDO calculations.


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CIS, TD

Gaussian 03 Online Manual Last update: 10 October 2003

This section lists all Link 0 commands, which are optional and precede the route section if present. See this page for a more detailed discussion of the scratch file naming commands. Link 0 commands may be up to 500 characters in length. %Mem= N

Sets the amount of dynamic memory used to N words (8 N bytes). The default is 6MW. N may be optionally followed by a units designation: KB, MB, GB, KW, MB or GW. %Chk= file

Locates and names the checkpoint file. %RWF= file

Locates and names a single, unified Read-Write file (old-style syntax). %RWF=loc1,size1,loc2,size2, ...

An alternate syntax is provided for splitting the Read-Write file among two or more disks (or file systems). Each location is followed by a maximum size for the file segment at that location. The default units for each size is words; the value may be optionally followed by KB, MB, GB, KW, MW or GW (with no intervening spaces) to indicate units. A value of -1 for any size parameter indicates that any and all available space may be used, and a value of 0 indicates that an existing segment should retain its current size. The locations may be either directory locations, or full pathnames. Note that directory specifications must include terminal slashes (on UNIX systems). %Int= spec

Locates and names the two-electron integral file(s). spec may take on either of the forms used for the Read-Write file (described above). %D2E= spec

Locates and names the two-electron integral derivative file(s). spec may take on either of the forms used for the Read-Write file (described above). %KJob L N [M ]

Tells the program to stop the run after the Mth occurrence of Link N. For example, %KJob L502 2 will cause the run to terminate after Link 502 has been run for the second time. M may be omitted; it defaults to 1.


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%NProcLinda= N

Requests that the job use up to N processors for distributed memory parallel execution. This capability is only available on some computer systems, and Gaussian must have been built with parallel processing enabled. On parallel machines, the number of processors to use in production runs is usually set in the Default.Route file, and the %NProcLinda Link 0 command is used to override this local default (e.g., to run debug jobs on a single processor even if the default is to use 4 processors). If %NProcLinda is not used, and no default is provided in the Default.Route file, then one processor is used. Note: the %NProc directive used in earlier program versions is obsolete. %NProcShared= N

Requests that the job use up to N processors for shared memory parallel execution on SMP multiprocessor computers. This capability is only available on some computer systems, and Gaussian must have been built with parallel processing enabled. On parallel machines, the number of processors to use in production runs is usually set in the %NProcShared Default.Route file, to and Linkprocessor 0 command to override local default (e.g., runthedebug jobs on a single evenisifused the default is tothis use 4

processors). If %NProcShared is not used, and no default is provided in the Default.Route file, then one processor is used. %Save

Causes Link 0 to save scratch files at the end of the run. By default, all non-specified scratch files are deleted and all named scratch files are saved when the run completes successfully. %NoSave

Causes Link 0 to following delete scratch files at theInend of awords, run, including files before that were named explicitly this directive. other if a file isany named %NoSave is encountered, it will not be saved. However, if the % directive naming the file appears after the %NoSave directive, the file will be retained. For example, these commands specify a name for the checkpoint file, and an alternate name and directory location for the read-write file, and cause only the checkpoint file to be saved at the conclusion of the Gaussian job: %RWF=/chem/scratch2/water %NoSave %Chk=water

Files to be deleted go here. Files to be saved go here.

If both %Save and %NoSave are specified, then the one appearing latest in the input file takes precedence. %Subst L N dir

Tells Link 0 to take the executable (.exe file) for a link from an alternate directory. For example %SUBST L913 /user/chem will cause /user/chem/l913.exe to be run instead of the default executable (in $g03root ). The directory specification should be in the usual


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format for the machine involved. Only the directory can be specified; the file name must have the standard form of lnnnn.exe, where nnnn is the Link number.

Specifying Non-Standard Routes

If a combination of options or links is required which is drastically different than a standard route, then a complete sequence of overlays and links with associated options can be read in. The job-type input section begins with the line: # NonStd

This is followed by one line for each desired overlay, in execution order, giving the overlay number, a slash, the desired options, another slash, the list of links to be executed, and finally a semicolon: Ov/Opt=val,Opt=val,.../Link,Link,...;

For example: 7/5=3,7=4/2,3,16;

specifies a run through the links 702, 703, and 716 (in this order), with option 5 set equal to 3 and option 7 equal to 4 in each of the links. If all options have their default value, the line would be 7//2,3,16;

A further feature of the route specification is the jump number . This is given in parentheses at the end of the link list, just before the semicolon. It indicates which overlay line is executed after completion of the current overlay. If it is omitted, the default value is +0, indicating that the program will proceed to the next line in the list (skipping no lines). If the jump number is set to -4, on the other hand, as in 7//2,3,16(-4);

then execution will continue counting the current line). with the overlay specified four route lines back (not This feature permits loops to be built into the route and is useful for optimization runs. An argument to the program chaining routine can override the jump. This is used during geometry optimizations to loop over a sequence of overlay lines until the optimization has been completed, at which point the line following the end of the loop is executed.


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Note that non-standard routes are not generally created from scratch but rather are built by printing out and modifying the sequence produced by the standard route most similar to that desired. This can be accomplished most easily with the testrt utility.

A Simple Route. The standard route: # RHF/STO-3G

causes the following non-standard route to be generated: 1/29=10000/1; 2/10=1,12=2/2; 3/11=1,25=14,30=1/1,2,3,11,14; 4/7=1/1; 5//2; 6/7=2,8=2,9=2,10=2,19=1,28=1/1; 99/5=1,9=1/99;

The resulting sequence of programs is illustrated below:

The basic sequence of program execution is identical to that found in any ab initio program, except that Link 1 (reading and interpreting the route section) precedes the actual calculation, and that Link 9999 (generating an archive entry) follows it. An AM1 single-point would be similar, except that only Link 301 (set up of basis set) would be included from overlay 3 and that Link 402 (code excerpted from the MOPAC program) would replace Link 502. Similarly, an MP4 single point has integral transformation (links 801 and 802) and the MP calculation (links 901, 909, 910, 911, 912, and 913) inserted


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after the population analysis and before Link 9999. Link 9999 automatically terminates the job step when it completes. A Route Involving Loops. The standard route: # RHF/STO-3G Opt

produces the following non-standard route: 1/10=7,29=10000/1,3; 2/10=1,12=2/2; 3/11=1,25=14,30=1/1,2,3,11,14; 4/7=1/1; 5//2; 6/7=2,8=2,9=2,10=2,28=1/1; 7/25=1,27=1,29=1/1,2,3,16; 1/10=7/3(1); 99//99; 2//2; 3/11=1,25=14,30=1/1,2,3,11,14; 4/5=5,7=1,16=2/1; 5//2; 7/27=1/1,2,3,16; 1//3(-5); 3/11=1,30=1,39=1/1,3; 6/7=2,8=2,9=2,10=2,28=1/1; 99/9=1/99;

The resulting sequence of program execution is illustrated below:


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Several considerations complicate this route: •

•

•

•

The first point of the optimization must be handled separately from later steps, since several actions must be performed only once. These include reading the initial Z-matrix and generating the initial orbitals. There must be a loop over geometries, with the optimization program (in this case the Berny optimizer, Link 103) deciding whether another geometry was required or the structure has been optimized. If a converged geometry is supplied, the program should calculate the gradients once, recognize that the structure is optimized, and quit. Population analysis and orbital printing should be done only at the first and last points, not at the relatively uninteresting intermediate geometries.


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The first point has been dealt with by having two basic sequences of integrals, guess, SCF, and integral derivatives in the route. The first sequence includes Link 101 (to read the initial geometry), Link 103 (which does its own initialization), and has options set to tell Link 401 to generate an initial guess. The second sequence uses geometries produced in Link 103 in the course of the optimization, and has options set to tell Link 401 to retrieve the wavefunction from the previous geometry as the initial guess for the next. The forward jump on the eighth line has the effect that if Link 103 exits normally (without taking any special action) the following line (invoking Link 9999) is skipped. Normally, in this second invocation of Link 103 the initial gradient will be examined and a new structure chosen. The next link to be executed will be Link 202, which processes the new Z-matrix, followed by the rest of the second energy+gradient sequence, which constitutes the main optimization loop. If the second invocation of Link 103 finds that the geometry is converged, it exits with a flag which suppresses the jump, causing Link 9999 to be invoked by the following line and the job to complete. Linesgradient 10-15 form thesecond main optimization loop. Thisinevaluates the integrals, wavefunction, and for the and subsequent points the optimization. It concludes with Link 103. If the geometry is still not converged, Link 103 chooses a new geometry and exits normally, causing the backward jump on line 15 to be executed, and the next line processed to be line 10, beginning a new cycle. If Link 103 finds that the geometry has converged, it exits and suppresses the jump, causing the concluding lines (16-18) to be processed. The concluding line generates the multipole integrals at the final geometry for use in Link 601, which prints the final multipole moments as well as the orbitals and population analysis if so requested. Finally, Link 9999 generates the archive entry and terminates the job step. Routes for AM1 optimizations are similar, with all but Link 301 omitted from the invocations of overlay 3, Link 402 replacing Link 501, and overlay 7 omitted (the MOPAC code in Link 402 computes the gradient information internally). MP and CI optimizations have the transformation and correlation overlays (8 and 9) and the postSCF gradient overlays (11 and 10, in that order) inserted before overlay 7. The same two phase route structure is used for numerical differentiation to produce frequencies or polarizabilities. The route for Opt=Restart is basically just the main loop from the original optimization, withdoes the special linesrestarting. for the first step omitted. The second invocation of Link 103 is kept and the actual KEYWORDS RELATED TO NON-STANDARD ROUTES ExtraLinks

Enables the inclusion of extra links in an otherwise standard route (the link names are specified as its options). They are always executed after all standard links in that


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occurrence of the overlay. For example, ExtraLinks=(L901) specifies that Link 901 is to be included in every occurrence of overlay 9, after any links in that overlay would be executed anyway. ExtraOverlays

Provides a mechanism customizing a routenew which is somewhat intermediate between using ExtraLinks and for reading in an entirely non-standard route. When specified, the program expects one or more lines of input after the blank line following the route section. These are overlay lines as described above. A blank line is then used to separate the last extra overlay line from the title section. The program will parse the standard route and add any extra overlay lines to the route just before the last overlay, Link 99 line: 99//99, generated in the standard route. This provides greater flexibility than the ExtraLinks keyword, since the user can provide new options to an additional link, instead of just accepting those which happen to be already there for a given overlay. Skip

This keyword user to skipbepast a certain number route generatedallows by thethe parser. It can invoked in two ways:of overlay lines in a standard Skip=Ovn Skip all overlays until the first occurrence of overlay n. Skip=M

Skip the first M overlays. Use

Allows the user to request an alternative algorithm for certain phases of the calculation. Most of the options are for debugging; they are described in the Gaussian 03 Programmer's Reference .

See also the discussion of the %KJob Link 0 command.

Program Development-Related Keywords The following keywords, useful for developing new methods and other debugging purposes, but not recommended for production level calculations, are described in the Gaussian 03 Programmer's Reference . • • • • • • •

ExtraLinks ExtraOverlays IOp2 and its synonyms MDV and Core IOp33 Restart Skip Use


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The Gaussian 03 IOps Reference also documents all internal options (IOps). They are also documented at www.gaussian.com/iops.htm.

Obsolete Keywords The following table lists obsolete keywords used by previous versions of Gaussian. While all of them are still supported by Gaussian 03, we strongly recommend converting to the up-to-date equivalents given in the table. Obsolete Keyword

Replacement Keyword & Option

Alter

Guess=Alter

BD-T

BD(T)

BeckeHalfandHalf

BHandH

Camp-King

SCF=Camp-King

CCSD-T

CCSD(T)

CubeDensity

cubegen

Cube=Divergence

cubegen

DIIS

SCF=DIIS

Direct

SCF=Direct

GridDensity

cubegen

Guess=Restart

SCF=Restart

MP2=Stingy

and VeryStingy none (options are a no-op)

NoDIIS NoExtrap

SCF=NoDIIS SCF=NoExtrap

NoRaff

Int=NoRaff

OldConstants

Constants=1979

Opt=AddRedundant

Opt=ModRedundant

OptCyc=n

Opt(MaxCyc=n)

OSS

GVB(OSS)

PlotDensity

cubegen

Prop=Grid

cubegen

QCID

CCD

QCISD-T

QCISD(T)

QCSCF

SCF=QC

Raff

Int=NoRaff

Save

none (Save is a no-op) SCF(Conver=n)

SCFCon=n


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SCFCyc=n

SCF(MaxCyc=n)

SCFDM

SCF=DM

SCFQC

SCF=QC

SCRF=Checkpoint

Field=EChk

VShift[=n]

SCF(VShift[=n])

Obsolete Utility

The chkmove utility, which converted checkpoint files to and from binary and text formats for transfer between different computer architectures, is no longer provided. Its functionality is now handled by formchk and unfchk .

CCD+STCCD

Specifies a coupled cluster calculation using double substitutions and evaluation of the contribution of single and triple excitations through fourth order using the CCD wavefunction. It is superseded by CCSD(T). ST4CCD is a synonym for CCD+STCCD. CPHF=DirInv

Invert the A-matrix directly. The default is the iterative solution, which is always preferable. Cube

This properties keyword can be used to evaluate molecular orbitals, the electrostatic potential, electron density, gradient,grid the(cube) norm of density gradient, and Laplacian the of the density over adensity 3 dimensional of the points. Its use is deprecated in favor of the cubegen utility. FormCheck

Requests that a formatted version of the checkpoint file be written at the end of a successful run. This keyword is deprecated in favor of the formchk utility. The formatted checkpoint file always has the name Test.FChk (note the mixed case), and it is placed into the default directory from which the job is run. This keyword cannot store transition densities or natural orbitals in the formatted checkpoint file. FORMCHK OPTIONS

All: Write everything to the formatted checkpoint file. ForceInt: Write forces in internal coordinates. ForceCart: Write forces in Cartesian coordinates. EField: Write the electric field properties (in Cartesian coordinates). OptInt: Write the intermediate structures from an optimization in internal coords. OptCart: Write the intermediate structures from an optimization in Cartesian coords.


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Basis: Write the basis set data (exponents, coefficients, etc.). MO: Write the Molecular orbitals. Spin: Write separate α and β components (default=total density). UseNO: If densities are requested, use the natural orbital representation (the default is the

density lower triangle). SCFDensity: Write the SCF density. CurrentDensity : Write the generalized density for the current method. AllDensities : Write all available densities. CurrTrans: Write the transition density between the ground and current state. GroundTrans: Write the transition densities between the ground and all excited states. GroundCurrTrans: Write all trans. densities involving either ground or current state. AllTrans: Write all transition densities. CurrEx1PDM: Write the CI-Singles 1PDM for the current state. AllEx1PDM: Write all CI-Singles 1PDMs. Geom=Coord

Indicates thatcan thebegeometry is in Cartesianwithout coordinates. Cartesian coordinates includedspecification in molecule specifications any special options being necessary. LST and LSTCyc

Requests that an initial guess for a transition structure be generated using Linear Synchronous Transit [575]. The LST procedure locates a maximum along a path connecting two structures and thus provides a guess for the transition structure connecting them. LST is not valid with AM1. Note that an LST calculation does not actually locate a proper transition state. However,

the structure resultinghowever, from an LST calculation be suitable as input for a subsequent . In general, the LST method may has been superseded by Opt=QST2 . Opt=TS Massage The Massage

keyword requests that the molecule specification and basis set data be modified after it is generated. This keyword is deprecated in favor of ExtraBasis, Charge, Counterpoise and other keywords. See below for its full description. Opt=EnOnly

Requests an optimization using a pseudo-Newton-Raphson method with a fixed Hessian and numerical differentiation of energies to produce gradients. This option requires that the Hessianand behigher read insaddle via ReadFC structures points. or RCFC. It can be used to locate transition Opt=FP

Requests the Fletcher-Powell optimization algorithm [144], which does not require analytic gradients.


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Opt=Grad

Requests a gradient optimization, using the default method unless another option is specified. This is the default whenever analytic gradients are available and is invalid otherwise. Opt=MNDOFC

Requests that the MNDO (or AM1, if possible) force constants be computed and used to start the (presumably ab initio) optimization. Opt=MS

Specifies the Murtaugh-Sargent optimization algorithm [145]. The Murtaugh-Sargent optimization method is an obsolete alternative, and is retained in Gaussian 03 only for backwards compatibility. Opt=UnitFC

Requests that a unit matrix be used instead of the usual valence force field guess for the Hessian. Output=PolyAtom

This requests output of an integral file in one variant of the format originated for the PolyAtom integrals program. The format produced by default is that used by the Caltech MQM programs, but the code in Link 9999 is easily modified to produce other variations on the same theme. Output=Trans

Write an MO coefficient file in Caltech (Tran2P5) format. This is only of interest to users of the Caltech programs. SCRF=OldPCM

The PCM model present in Gaussian 94 may be accessed using this option to SCRF. It requires the dielectric constant of the solvent and the number of points per sphere as input. The radii of the spheres may optionally be specified for each atom type by including the ReadRadii option. Alternate radii for each atom for use in fitting potentials may be input via the ReadAtRadii option. SCRF=DPCM

Uses the polarizable dielectric model [285,286,287], which corresponds to the Gaussian 98 SCRF=PCM option except for some minor implementation details [302]. This model is no longer recommended for general use. The default SCRF method is IEF-PCM. SCRF=Numer

Force numerical SCRF rather than analytic. This keyword is required for multiple orders beyond Dipole. This option implies the use of spherical cavities, which are not recommended. No gradients are available for this option.


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SCRF=Dipole The options Dipole, Quadrupole, Octopole,nd Hexadecapole specify the order of multipole to use in the SCRF calculation. All but Dipole require that the Numer option

be specified as well. SCRF=Cards Begin the SCRF=Numer calculation with a previously computed reaction field read

from the input stream, immediately after the line specifying the dielectric constant and radius (three free-format reals). %SCR

Used to specify the location of the .SCR scratch file. Stable=Symm

Retain symmetry restrictions. NoSymm relaxes symmetry restrictions and is the default. Description of Cube

The Cube properties keyword can be used to evaluate molecular orbitals, the electrostatic potential, the electron density, density gradient, the norm of the density gradient, and Laplacian of the density over a 3 dimensional grid (cube) of points. Its use is deprecated in favor of the cubegen utility. Cube evaluates the electron density (corresponding to the Density option). By default, Which density is used is controlled by the Density keyword; use Density=Current to evaluate the cube over the density from a correlated or CI-Singles wavefunction instead of the default Hartree-Fock density.

Note that only one of the available quantities can be evaluated within any one job step. Save the checkpoint file (using %Chk ), and include Guess=(Read,Only ) Density=Checkpoint in the route section of a subsequent job (or job step) in order to evaluate a different quantity without repeating any of the other steps of the calculation. Gaussian provides reasonable defaults for grids, so Cube does not require that the cube

be specified by the user. However, the output filename must always be provided (see below). Alternatively, Cube may be given a parameter specifying the number of points to use per "side" (the default is 80). For example, Cube=100 specifies a grid of 1,000,000 points (1003), evenly distributed over the rectangular grid generated by the program (which is not necessarily a cube). In addition, the input format used by earlier versions of Gaussian


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is still supported; Cube=Cards indicates that a grid will be input. It may be used to specify a grid of arbitrary size and shape. The options Coarse, Medium and Fine may also be specified as the parameter to Cube. They correspond to densities of 3, 6 and 12 points/Bohr, respectively. These options are designed sizes. to facilitate uniform quality in grid sampling across the range of molecular The files created by Cube can be manipulated using the cubman utility. Note that Pop=None will inhibit cube file creation. INPUT FORMAT

When the user elects to provide it, the grid information is read from the input stream. The first line-required for all Cube jobs-gives a file name for the cube file. Subsequent lines, Cube=Cards, must conform to format (I5,3F12.6), which are included only with according to the following syntax: Output-file-name IFlag, X 0, Y 0, Z0 initial point. N 1, X 1, Y 1, Z1 size in the X-direction. N 2, X 2, Y 2, Z2 size in the Y-direction. N 3, X 3, Y 3, Z3 size in the Z-direction.

Required in all Cube jobs. Output unit number and Number of points and stepNumber of points and stepNumber of points and step-

IFlag is the output unit number. If IFlag is less than 0, then a formatted file will be

produced; otherwise, an unformatted file will be written.

If N1<0 the input cube coordinates are assumed to be in Bohr, otherwise, they are interpreted as Angstroms (this keyword is not affected by the setting of the Units keyword). |N 1| is used as the number of X-direction points in any case. Note that the three axes are used exactly as specified; they are not orthogonalized, so the grid need not be rectangular. If the Orbitals option is selected, the cube filename (or cube filename and cube specification input) is immediately followed by a list of the orbitals to evaluate, in freeformat, terminated by a blank line. In addition to numbers for the orbitals (with β orbitals numbered starting at N +1), the following abbreviations can appear in the list: HOMO

The highest occupied molecular orbital LUMO

The lowest unoccupied molecular orbital


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OCCA

All occupied (α) orbitals OCCB

All β occupied orbitals for UHF ALL

All orbitals VALENCE

All occupied non-core orbitals VIRTUALS

All virtual orbitals See the examples section for sample input files. OUTPUT FILE FORMATS

All values in the cube file are in atomic units, regardless of the input units. Using the default input to Cube produces an unformatted output file (you can use the cubman utility to convert it to a formatted version if you so desire). When the Cards option is specified, then the IFlag parameter's sign determines the output file type. If IFlag >0, the output is unformatted. If IFlag <0, the output is formatted. All values in the cube file are in atomic units, regardless of the input units. N 1* N 2 For density potential unformatted files each have row one is row per record records eachand of length N 3).grids, For formatted output, written out in(i.e., format (6E13.5). In this case, if N 3 is not a multiple of six, then there may be blank space in some lines.

The norm of the density gradient and the Laplacian are also scalar (i.e., one value per point), and are written out in the same manner. Density+gradient grids are similar, but with two writes for each row (of lengths N 3 and 3* N 3). Density + gradient + Laplacian grids have 3 writes per row (of lengths N 3, 3* N 3, and N 3) For example, for a density cube, the output file looks like this: NAtoms, X-Origin, Y-Origin, Z-Origin N1, X1, Y1, Z1 # of increments in the slowest running direction N2, X2, Y2, Z2 N3, X3, Y3, Z3 # of increments in the fastest running direction IA1, Chg1, X1, Y1, Z1 Atomic number, charge, and coordinates of the first

atom ...


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IAn, Chgn, Xn, Yn, Zn

Atomic number, charge, and coordinates of the last

atom (N 1*N 2) records, each of length N 3

Values of the density at each point in the grid

Note that a separate write is used for each record. For molecular orbital output, NAtoms will be less than zero, and an additional record follows the data for the final atom (in format 10I5 if the file is formatted): NMO, (MO(I),I=1,NMO)

Number of MOs and their numbers

If N MO orbitals were evaluated, then each record is N MO* N 3 long and has the values for all orbitals at each point together. READING CUBE FILES WITH FORTRAN PROGRAMS

If one wishes to read the values of the density, Laplacian, or potential back into an array dimensioned X( N 3 ,N 2 ,N 1) code like the following Fortran loop may be used: Do 10 I1 = 1, N1 Do 10 I2 = 1, N2 Read(n,'(6E13.5)') (X(I3,I2,I1),I3=1,N3) 10 Continue

where n is the unit number corresponding to the cube file. If the origin is (X0,Y0,Z0), and the increment is (X1,Y1,Z1), then point (I1,I2,I3) has the coordinates: X-coordinate: X0+(I1-1)*X1+(I2-1)*X2+(I3-1)*X3 Y-coordinate: Y0+(I1-1)*Y1+(I2-1)*Y2+(I3-1)*Y3 Z-coordinate: Z0+(I1-1)*Z1+(I2-1)*Z2+(I3-1)*Z3

The output is similar if the gradient or gradient and Laplacian of the charge density are also requested, except that in these cases there are two or three records, respectively, written for each pair of I1, I2 values. Thus, if the density and gradient are to be read into arrays D( N 3,N2 ,N 1), G(3, N 3 ,N 2 ,N 1), RL( N 3, N 2 ,N 1), a correct set of Fortran loops would be: Do 10 I1 = 1, N1 Do 10 I2 = 1, N2 Read(n,'(6F13.5)') (D(I3,I2,I1),I3=1,N3) Read(n,'(6F13.5)') ((G(IXYZ,I3,I2,I1),IXYZ=1,3), I3=1,N3) 10 Continue

where again n is the unit number corresponding to the cube file.


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GRID-RELATED OPTIONS

N

Number of points to use per "side" (the default is 80). For example, Cube=100 specifies a grid of 1,000,000 points (1003), evenly distributed over the rectangular grid generated by the program (which is not necessarily a cube). Coarse

3 points/Bohr. Medium

6 points/Bohr. Fine

12 points/Bohr. CUBE CONTENTS OPTIONS Density

Compute just the density values. Cannot be combined with the Volume keyword or the Cube=Orbitals option. Potential

Compute the electrostatic potential at each point. Gradient

Compute the density and gradient. Laplacian

Compute the Laplacian of the density ∇2ρ). Divergence is a synonym for Laplacian. NormGradient

Compute the norm of the density gradient at each point. Orbitals

Compute the values of one or more molecular orbitals at each point. MO is a synonym for Orbitals. Cannot be combined with the Volume keyword or the Cube=Density option. FrozenCore

Remove the SCF core density. This is the default for the density, and is not allowed for the potential. FC is a synonym for FrozenCore. Full

Evaluate the density including all electrons.


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Total

Use the total density. This is the default Alpha

Use only the alpha spin density. Beta

Use only the beta spin density. Spin

Use the spin density (difference between alpha and beta densities). Cards

Read grid specification from the input stream (as described above). Arbitrary

Read in a list of arbitrary points.

Density, cubegen

The following job will create a cube file named orbitals.cube

containing the HOMO

and LUMO. #n rhf/6-31g* 5d scf=tight cube=(orbitals) test HOMO and LUMO in default cube 0,1 O H,1,R2 F,1,R3,2,A3 Variables: R2=0.96 R3=1.42 A3=109.47122063 orbitals.cube homo lumo

The following cube file illustrates the method for defining your own cube via Cube=Cards: # rhf/6-31g* 5d scf=tight cube=(density,cards) test


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Density cube with user-defined cube 0,1 O H,1,R2 F,1,R3,2,A3 Variables: R2=0.96 R3=1.42 A3=109.47122063 density.cube -51 -2.0 40 0.1 40 0.0 20 0.0

-2.0 0.0 0.1 0.0

-1.0 0.0 0.0 0.1

Description of Massage The Massage keyword requests that the molecule specification and basis set data be modified after it is generated. This keyword is deprecated in favor of ExtraBasis, Charge, Counterpoise and other keywords.

The Massage keyword thus makes it possible to add additional uncontracted basis functions to a standard basis set. Common polarization or diffuse functions can be added in this way to standard basis sets for which these functions are not internally defined. For example, diffuse functions could be added to the 3-21G basis set to form 3-21+G. Similarly, polarization functions might be added to 6-311G to form a 6-311G(5d3f) basis, which is larger than the largest internally stored 6-311G-based basis set, 6-311G(3d1f). The standard basis functions are assigned to atoms before Massage alterations take place, while the number of electrons is computed from the atomic numbers after the modifications. Calculations with massaged basis set data cannot generate archive entries, and do not take advantage of molecular symmetry. Some of this functionality of Massage has been superceded by the ExtraBasis keyword. Point charges may also be specified for single point energy calculations using Charge. Massage may also be used for counterpoise calculations and BSSE (see the examples).

INPUT Massage requires one or more lines of input in the following format:

center , func, exp, [cX, cY, cZ ]


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where center is the center number (numbering follows the ordering of the molecule specification section), func is a code indicating the type of modification (see below), exp is the exponent of Gaussian or new nuclear charge (a value of 0 says to add a ghost atom), and cX,cY,cZ are the coordinates of the point charge in Angstroms when func is -1 (see below). A blank line terminates this input section. func can take on these values: 0 or Nuc

Change the nuclear charge. 1 or SP

Add an SP shell. 2 or D

Add a D shell. 3 or P

Add a P shell. 4 or S

Add an S shell. 5 or F

Add an F shell. -1 or Ch

Add a point charge. Note that this keyword is not affected by the setting of the Units keyword, and its input is always interpreted as Angstroms.

Charge, ExtraBasis, Gen, Counterpoise

Adding Point Charges. The following input file adds point charges to a calculation on water using the Massage keyword. Note: This is usually done with the Charge keyword

and input. # RHF/6-31G(d) Massage Test Water with point charges


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0 1 O -0.464 0.177 H -0.464 1.137 H 0.441 -0.143

0.0 0.0 0.0

0 ch 2.0 1.0 1.0 1.0 0 ch 2.5 1.0 -1.0 1.0

Adding Basis Functions. The following input adds functions

to the D95 basis set (in order to reproduce a calculation from the literature that used a non-standard basis set). Note: This is usually done with the ExtraBasis keyword and input. # RQCISD(Full)/D95 Freq=Numer Massage Test H2O Frequencies at QCISD(Full)/DZP 0 1 O H 1 R H 1 R 2 A R=0.961882 A=104.612551 1 D 0.85 2 P 1.0 3 P 1.0

Computing Counterpoise Corrections Manually. The following input file performs a counterpoise calculation. Note the the Massage keyword is not used. The atoms to be removed are simply designated with the ghost atom suffix (Bq). Note: The Counterpoise

keyword is now used to perform this type of calculation. # b3lyp/3-21G** nosymm scf=tight test HBr + H2O manual counterpoise calculation, H2O removed 0 1 H 0.685176 Br -0.771917 O-Bq 2.536864 H-Bq 3.015128 H-Bq 3.021888

-0.004924 0.000050 -0.000136 0.789231 -0.784986

-0.026973 0.001967 -0.051401 0.184042 0.185282

Utility Programs This page discusses various utility programs included with Gaussian 03. The utilities are discussed in alphabetical order within this chapter.


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Most utilities are available for both UNIX and Windows versions of Gaussian. However, be sure to consult the release notes accompanying the program for information pertaining to specific operating systems. The following lists the available utilities and their functions (starred items are included on the Gaussian 03W Utilities menu): Converts checkpoint files from previous program versions to Gaussian 03 format. chkchk * Displays the route and title sections from a checkpoint file. cubegen* Standalone cube generation utility. Manipulates Gaussian-produced cubes of electron density and electrostatic cubman* potential (allowing them to be added, subtracted, and so on). Converts a binary checkpoint file into an ASCII form suitable for use with formchk * visualization programs and for moving checkpoint files between different types of computer systems. Prints frequency and thermochemistry data from a checkpoint file. Alternate freqchk * isotopes, temperature, pressure and scale factor can be specified for the thermochemistry analysis. freqmem Determines memory requirements for frequency calculations. gauopt Performs optimizations of variables other than molecular coordinates. On-line help for Gaussian. ghelp Standalone molecular mechanics program. mm newzmat* Conversion between a variety of molecular geometry specification formats. c8603

testrt* unfchk *

Route section syntax checker and non-standard route generation. Convert a formatted checkpoint file back to its binary form (e.g., after moving it from a different type of computer system).

GAUSS_MEMDEF Environment Variable The GAUSS_MEMDEF environment variable may be used to increase the memory available to utilities do not offer such an option themselves. Its value should be set to the desired amountwhich of memory in words.

This page presents a brief overview of traditional Z-matrix descriptions of molecular systems.


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Using Internal Coordinates

Each line of a Z-matrix gives the internal coordinates for one of the atoms within the molecule. The most-used Z-matrix format uses the following syntax: Element-label , atom 1, bond-length, atom 2, bond-angle, atom 3, dihedral-angle [, format-code]

Although these examples use commas to separate items within a line, any valid separator may be used. Element-label is a character string consisting of either the chemical symbol for the atom or its atomic number. If the elemental symbol is used, it may be optionally followed by other alphanumeric characters to create an identifying label for that atom. A common practice is to follow the element name with a secondary identifying integer: C1, C2, etc. Atom1, atom2, atom3 are the labels for previously-specified atoms and are used to define

the currentspecification atoms' position. Alternatively, atoms' of line numberswhere withinthe thecharge molecule section may be usedtheforother the values variables, and spin multiplicity line is line 0. The position of the current atom is then specified by giving the length of the bond joining it to atom1, the angle formed by this bond and the bond joining atom1 and atom2, and the dihedral (torsion) angle formed by the plane containing atom1, atom2 and atom3 with the plane containing the current atom, atom1 and atom2. Note that bond angles must be in the range 0º < angle < 180º. Dihedral angles may take on any value. The optional format-code parameter specifies the format of the Z-matrix input. For the syntax being describedfollow here, this code is Z-matrix always 0.specification This code is needed additional parameters the normal data, as only in anwhen ONIOM calculation. As an initial example, consider hydrogen peroxide. A Z-matrix for this structure would be: H O 1 0.9 O 2 1.4 1 105.0 H 3 0.9 2 105.0 1 120.0

The first line of the Z-matrix simply specifies a hydrogen. The next line lists an oxygen atom and specifies the internuclear distance between it and the hydrogen as 0.9 Angstroms. The third line defines another oxygen with an O-O distance of 1.4 Angstroms (i.e., from atom 2, the other oxygen) and having an O-O-H angle (with atoms 2 and 1) of 105 degrees. The fourth and final line is the only one for which all three internal coordinates need be given. It defines the other hydrogen as bonded to the second oxygen with an H-O distance of 0.9 Angstroms, an H-O-O angle of 105 degrees and a H-O-O-H dihedral angle of 120 degrees.


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Variables may be used to specify some or all of the values within the Z-matrix. Here is another version of the previous Z-matrix: H O 1 R1 O 2 R2 1 A H 3 R1 2 A 1 D Variables: R1 0.9 R2 1.4 A 105.0 D 120.0

Symmetry constraints on the molecule are reflected in the internal coordinates. The two H-O distances are specified by the same variable, as are the two H-O-O bond angles. When such a Z-matrix is used for a geometry optimization in internal coordinates (Opt=Z-matrix), the values of the variables will be optimized to locate the lowest energy structure. For a full optimization (FOpt), the variables are required to be linearly independent and include all degrees of freedom in the molecule. For a partial optimization (POpt), variables in a second section (often labeled Constants:) are held fixed in value while those in the first section are optimized: Variables: R1 0.9 R2 1.4 A 105.0 Constants: D 120.0

See the examples in the discussion of the Opt keyword for more information about optimizations in internal coordinates. Mixing Internal and Cartesian Coordinates

Cartesian coordinates are actually a special case of the Z-matrix, as in this example: C C H H H

0.00 0.00 1.02 -0.51 -0.51

0.00 0.00 0.00 -0.88 0.88

0.00 1.52 -0.39 -0.39 -0.39

H H H

-1.02 0.51 0.51

0.00 -0.88 0.88

1.92 1.92 1.92

It is also possible to use both internal and Cartesian coordinates within the same Zmatrix, as in this example: O 0 xo C 0 0.

0. yc

zo 0.


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C N H H H H H

0 0. -yc 0. 0 xn 0. 0. 2 r1 3 a1 1 b1 2 r2 3 a2 1 b2 3 r1 2 a1 1 -b1 3 r2 2 a2 1 -b2 4 r3 2 a3 3 d3 Variables: xo -1. zo 0. yc 1. xn 1. r1 1.08 r2 1.08 r3 1.02 a1 125. a2 125. d3 160. b1 90. b2 -90.

This Z-matrix has several features worth noting: •

•

•

The variable names for the Cartesian coordinates are given symbolically in the same manner as for internal coordinate variables. The integer 0 after the atomic symbol indicates symbolic Cartesian coordinates to follow. Cartesian coordinates can be related by a sign change just as dihedral angles can.

Alternate Z-matrix Format

An alternative Z-matrix format allows nuclear positions to be specified using two bond angles rather than a bond angle and a dihedral angle. This is indicated by a 1 in an additional field following the second angle (this field defaults to 0, which indicates a dihedral angle as the third component): C4 O1 0.9 C2 120.3 O2 180.0 0 C5 O1 1.0 C2 110.4 C4 105.4 1 C6 O1 R C2 A1 C3 A2 1

The first line uses a dihedral angle while the latter two use a second bond angle. Using Dummy Atoms

This section will illustrate the use of dummy atoms within Z-matrices, which are represented by the pseudo atomic symbol X. The following example illustrates the use of a dummy atom to fix the three-fold axis in C3v ammonia: N X 1 1. H 1 nh 2 hnx


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H 1 nh 2 hnx 3 120.0 H 1 nh 2 hnx 3 -120.0 nh 1.0 hnx 70.0

The position dummy on the axis is irrelevant, andangle the distance couldand have been replacedofbythe any other positive number. hnx is the between1.0 anused NH bond the threefold axis. Here is a Z-matrix for oxirane: X C1 X halfcc O X ox C1 90. C2 X halfcc O 90. C1 180.0 H1 C1 ch X hcc O hcco H2 C1 ch X hcc O -hcco H3 C2 C2 H4

ch ch

X hcc X hcc

O -hcco hcco O

halfcc 0.75 ox 1.0 ch 1.08 hcc 130.0 hcco 130.0

This example illustrates two points. First, a dummy atom is placed at the center of the CC bond to help constrain the cco triangle to be isosceles. ox is then the perpendicular distance from O to the C-C bond, and the angles oxc are held at 90 degrees. Second, some of the entries in the Z-matrix are represented by the negative of the dihedral angle variable hcco. The following examples illustrate the use of dummy atoms for specifying linear bonds. Geometry optimizations in internal coordinates are unable to handle bond angles of l80 degrees which occur in linear molecular fragments, such as acetylene or the C4 chain in butatriene. Difficulties may also be encountered in nearly linear situations such as ethynyl groups in unsymmetrical molecules. These situations can be avoided by introducing dummy atoms along the angle bisector and using the half-angle as the variable or constant: N C 1 cn X 2 1. 1 90. H 2 ch 3 90. 1 180. cn 1.20 ch 1.06


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Similarly, in this Z-matrix intended for a geometry optimization, half represents half of the NCO angle which is expected to be close to linear. Note that a value of half less than 90 degrees corresponds to a cis arrangement: N C X O H

1 2 2 4

cn 1. 1 half co 3 half 1 180.0 oh 2 coh 3 0.0

cn 1.20 co 1.3 oh 1.0 half 80.0 coh 105.

Model Builder Geometry Specifications

The model builder is another facility with within quickly specifying sorts of molecular systems. It is requested theGaussian ModelAfor or ModelB options to certain the Geom keyword, and it requires additional input in a separate section within the job file. The basic input to the model builder is called a short formula matrix, a collection of lines, each of which defines an atom (by atomic symbol) and its connectivity, by up to six more entries. Each of these can be either an integer, which is the number of the line defining another explicitly specified atom to which the current atom is bonded, or an atomic symbol (e.g. H, F) to which the current atom is connected by a terminal bond, or a symbol for a terminal functional group which is bonded to the current atom. The functional groups currently available are OH, NH2, Me, Et, NPr, IPr, NBu, IBu, and TBu. The short formula matrix also implicitly defines the rotational geometry about each bond in the following manner. Suppose atoms X and Y are explicitly specified. Then X will appear in row Y and Y will appear in row X. Let I be the atom to the right of X in row Y and J be the atom to the right of Y in row X. Then atoms I and J are put in the trans orientation about the X-Y bond. The short formula matrix may be followed by optional lines modifying the generated structure. There are zero or more of each of the following lines, which must be grouped together in the order given here: AtomGeom, I ,Geom

Normally the local an atom is defined in byethylene the number and types of bond about the atom (e.g.,geometry carbon inabout methane is tetrahedral, is trigonal, etc.). All bond angles at one center must be are equal. The AtomGeom line changes the value of the bonds at center I . Geom may be the angle as a floating point number, or one of the strings Tetr, Pyra, Trig, Bent, or Line. BondRot, I , J , K , L,Geom

This changes the orientations of the I - J and K - L bonds about the J - K bond. Geom is either


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the dihedral angle or one of the strings Cis (≥0), Trans (≥180), Gaup (≥+60), or Gaum (≥-60). BondLen, I , J , NewLen

This sets the length of the I - J bond to NewLen (a floating point value). The model builder can only build structures with atoms in their normal valencies. If a radical is desired, its extra valence can be "tied down" using dummy atoms, which are specified by a minus sign before the atomic symbol (e.g., -H). Only terminal atoms can be dummy atoms. The two available models (A and B) differ in that model A takes into account the type (single, double, triple, etc.) of a bond in assigning bond lengths, while model B bond lengths depend only on the types of the atoms involved. Model B is available for all atoms from H to Cl except He and Ne. If Model A is requested and an atom is used for which no Model A bond length is defined, the appropriate Model B bond length is used instead.

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