GAUSSIAN
Encyclopedia
Gaussian is a computational chemistry
software program initially released in 1970 by John Pople
and his research group at Carnegie-Mellon University as Gaussian 70. It has been continuously updated since then. The name originates from Pople's use of Gaussian orbitals to speed up calculations compared to those using Slater-type orbitals, a choice made to improve performance on the limited computing capacities of then-current computer hardware for Hartree-Fock
calculations. The current version of the program is Gaussian 09. Originally available through the Quantum Chemistry Program Exchange, it was later licensed out of CMU, and since 1987 has been developed and licensed by Gaussian, Inc.
Gaussian quickly became a popular and widely-used electronic structure program. Prof. Pople and his students and post-docs were among those who pushed the development of the package, including cutting-edge research in quantum chemistry
and other fields.
. The controversy was also noted in 1999 by Chemical and Engineering News (repeated without additional content in 2004), and in 2000 the World Association of Theoretically Oriented Chemists Scientific Board, held a referendum of its executive board members on this issue with a majority (23 of 28) approving the resolution opposing the restrictive licenses.
Gaussian corporation disputes the accuracy of these descriptions of its policy and actions, noting that all of the listed institutions do in fact have licenses for everyone but directly competing researchers. They also state that not licensing competitors is in fact standard practice in the software industry. Finally, they note that few commercial software packages in computational chemistry offer source code to anyone at any price.
Computational chemistry
Computational chemistry is a branch of chemistry that uses principles of computer science to assist in solving chemical problems. It uses the results of theoretical chemistry, incorporated into efficient computer programs, to calculate the structures and properties of molecules and solids...
software program initially released in 1970 by John Pople
John Pople
Sir John Anthony Pople, KBE, FRS, was a Nobel-Prize winning theoretical chemist. Born in Burnham-on-Sea, Somerset, England, he attended Bristol Grammar School. He won a scholarship to Trinity College, Cambridge in 1943. He received his B. A. in 1946. Between 1945 and 1947 he worked at the Bristol...
and his research group at Carnegie-Mellon University as Gaussian 70. It has been continuously updated since then. The name originates from Pople's use of Gaussian orbitals to speed up calculations compared to those using Slater-type orbitals, a choice made to improve performance on the limited computing capacities of then-current computer hardware for Hartree-Fock
Hartree-Fock
In computational physics and chemistry, the Hartree–Fock method is an approximate method for the determination of the ground-state wave function and ground-state energy of a quantum many-body system....
calculations. The current version of the program is Gaussian 09. Originally available through the Quantum Chemistry Program Exchange, it was later licensed out of CMU, and since 1987 has been developed and licensed by Gaussian, Inc.
Gaussian quickly became a popular and widely-used electronic structure program. Prof. Pople and his students and post-docs were among those who pushed the development of the package, including cutting-edge research in quantum chemistry
Quantum chemistry
Quantum chemistry is a branch of chemistry whose primary focus is the application of quantum mechanics in physical models and experiments of chemical systems...
and other fields.
Standard Capabilities
According to the most recent Gaussian manual, the package can do:- Molecular mechanicsMolecular mechanicsMolecular mechanics uses Newtonian mechanics to model molecular systems. The potential energy of all systems in molecular mechanics is calculated using force fields...
.- AMBERAMBERAMBER is a family of force fields for molecular dynamics of biomolecules originally developed by the late Peter Kollman's group at the University of California, San Francisco. AMBER is also the name for the molecular dynamics software package that simulates these force fields...
. - UFFUniversal force fieldUniversal force field is an all atom potential containing parameters for every atom. The force field parameters are estimated using general rules based only on the element, its hybridization, and its connectivity....
. - DREIDING force field.
- AMBER
- Semi-empirical calculations.
- AM1, PM3PM3 (chemistry)PM3, or Parameterized Model number 3, is a semi-empirical method for the quantum calculation of molecular electronic structure in computational chemistry. It is based on the Neglect of Differential Diatomic Overlap integral approximation....
, CNDOCNDO/2CNDO is the abbreviation for Complete Neglect of Differential Overlap. Although CNDO is based on quantum chemistry, it is more specifically one of the first semi-empirical quantum chemistry methods. It uses two approximations:...
, INDOINDOINDO stands for Intermediate Neglect of Differential Overlap. It is a semi-empirical quantum chemistry method that is a development of the complete neglect of differential overlap method introduced by John Pople...
, MINDO/3MINDOMINDO, or Modified Intermediate Neglect of Differential Overlap is a semi-empirical method for the quantum calculation of molecular electronic structure in computational chemistry. It is based on the Intermediate Neglect of Differential Overlap method of John Pople. It was developed by the group...
, MNDOMNDOMNDO, or Modified Neglect of Differential Overlap is a semi-empirical method for the quantum calculation of molecular electronic structure in computational chemistry. It is based on the Neglect of Differential Diatomic Overlap integral approximation. Similarly, this method replaced the earlier...
.
- AM1, PM3
- SCF methods.
- RestrictedHartree-FockIn computational physics and chemistry, the Hartree–Fock method is an approximate method for the determination of the ground-state wave function and ground-state energy of a quantum many-body system....
, UnrestrictedUnrestricted Hartree-FockUnrestricted Hartree–Fock theory is the most common molecular orbital method for open shell molecules where the number of electrons of each spin are not equal...
, and Restricted Open-shell Hartree-FockRestricted Open-shell Hartree-FockRestricted open-shell Hartree–Fock is a variant of Hartree–Fock theory for open shell molecules. It uses doubly occupied molecular orbitals as far as possible and then singly occupied orbitals for the unpaired electrons...
.
- Restricted
- Møller-Plesset perturbation theoryMøller-Plesset perturbation theoryMøller–Plesset perturbation theory is one of several quantum chemistry post-Hartree–Fock ab initio methods in the field of computational chemistry...
(MP2, MP3, MP4, MP5). - Built-in DFTDensity functional theoryDensity functional theory is a quantum mechanical modelling method used in physics and chemistry to investigate the electronic structure of many-body systems, in particular atoms, molecules, and the condensed phases. With this theory, the properties of a many-electron system can be determined by...
methods.- B3LYP and other Hybrid functionalHybrid functionalHybrid functionals are a class of approximations to the exchange-correlation energy functional in density functional theory that incorporate a portion of exact exchange from Hartree-Fock theory with exchange and correlation from other sources...
s. - Exchange functionals: PBE, MPW, PW91, Slater, X-alpha, Gill96, TPSS.
- Correlation functionals: PBE, TPSS, VWN, PW91, LYP, PL, P86, B95.
- B3LYP and other Hybrid functional
- ONIOMONIOMThe ONIOM is a computational approach developed by Morokuma and co-workers...
(QM/MMQM/MMThe hybrid QM/MM approach is a molecular simulation method that combines the strength of both QM and MM calculations, thus allowing for the study of chemical processes in solution and in proteins. The QM/MM approach was introduced in the 1976 paper of Warshel and Levitt .An important advantage...
method) up to three layers. - Complete active spaceComplete active spaceIn quantum chemistry, a complete active space is a type of classification of molecular orbitals. Spatial orbitals are classified as belonging to three classes:* core, always hold two electrons* active, partially occupied orbitals...
(CAS) and Multi-configurational self-consistent fieldMulti-configurational self-consistent fieldMulti-configurational self-consistent field is a method in quantum chemistry used to generate qualitatively correct reference states of molecules in cases where Hartree–Fock and density functional theory are not adequate...
calculations - Coupled clusterCoupled clusterCoupled cluster is a numerical technique used for describing many-body systems. Its most common use is as one of several quantum chemical post-Hartree–Fock ab initio quantum chemistry methods in the field of computational chemistry...
calculations. - QCIQuadratic configuration interactionQuadratic configuration interaction is an extension of Configuration interaction that corrects for size-consistency errors in the all singles and double excitation CI methods ....
methods. - Quantum chemistry composite methodsQuantum chemistry composite methodsQuantum chemistry composite methods are computational chemistry methods that aim for high accuracy by combining the results of several calculations. They combine methods with a high level of theory and a small basis set with methods that employ lower levels of theory with larger basis sets...
- CBS-QB3, CBS-4, CBS-Q, CBS-Q/APNO, G1, G2, G3, W1 high-accuracy methods.
Major Release history
Gaussian70, Gaussian76, Gaussian77, Gaussian78, Gaussian80, Gaussian82, Gaussian83, Gaussian85, Gaussian86, Gaussian88, Gaussian90, Gaussian 92, Gaussian93, Gaussian 94, Gaussian95, Gaussian96, Gaussian 98, Gaussian 03, Gaussian 09License controversy
In the past, Gaussian, Inc. has attracted controversy for its licensing terms that stipulate that researchers who develop competing software packages are not permitted to use the software. Some scientists consider these terms overly restrictive. The anonymous group bannedbygaussian.org has published a list of scientists who it claims are not permitted to use GAUSSIAN software. These assertions were repeated by Jim Giles in 2004 in NatureNature (journal)
Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...
. The controversy was also noted in 1999 by Chemical and Engineering News (repeated without additional content in 2004), and in 2000 the World Association of Theoretically Oriented Chemists Scientific Board, held a referendum of its executive board members on this issue with a majority (23 of 28) approving the resolution opposing the restrictive licenses.
Gaussian corporation disputes the accuracy of these descriptions of its policy and actions, noting that all of the listed institutions do in fact have licenses for everyone but directly competing researchers. They also state that not licensing competitors is in fact standard practice in the software industry. Finally, they note that few commercial software packages in computational chemistry offer source code to anyone at any price.