Gaussian manual

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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 AboutGaussian 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 Additional Information About Z-Matrices References

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 isfree-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 thedevelopment 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 momentumfunctions, 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" means (using some disk storage of integrals), or "conventional" means (with all AO integrals on disk). Use of density fitting to speed up the Coulomb part of pure DFT calculations [35,36]. Numerical quadrature to compute DFT XC energiesand 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 areavailable. 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 and double substitutions (CCSD) [68,69,70,71], Quadratic Configuration Interaction using single and double substitutions(QCISD) [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...
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