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Pure Appl. Chem., Vol. 71, No. 10, pp. 1919-1981, 1999

Glossary of terms used in theoretical organic chemistry

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Gaussian type orbital (GTO) - An exponential function centered on an atom, the general expression for which is given by

c (a, r) = Nxiyjzkexp(-ar2)

where i, j, k are positive integers or zero and a is the orbital exponent. Orbitals of s, p, and d type result when i + j + k = 0, 1, 2 respectively. Linear combinations of primitive gaussians are used to form the actual basis functions that are called contracted gaussians.The great convenience of GTOs lies in the fact that evaluation of the molecular integrals needed in ab initio quantum mechanical methods of calculation is performed much more efficiently as compared with Slater type atomic orbitals.

Generalized Valence Bond (GVB) method - A multiconfigurational method that uses a limited set of valence bond configurations in the conventional multiconfiguration SCF method.

Ghost orbitals - see Counterpoise correction.

Gradient norm - see Energy gradient.

Graph - A representation consisting of points (vertices) connected by lines (edges). A graph is a topological, but not a geometric object.

Graph automorphism group - The set of all permutations of graph vertices in which adjacent vertices remain adjacent.

Ground state - The lowest energy state of a chemical entity.

[A] [B] [C] [D] [E] [F] [G] [H] [I] [J-K] [L] [M]
[N] [O] [P] [Q-R] [S] [T] [U-V] [W-Z]

> Abstract
> General remarks
> Arrangement

> Fundamental physical constants used in the glossary
> References
> Appendix. Glossary of acronyms of terms used in theoretical organic chemistry

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