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Neglect of four‐ and approximation of one‐, two‐, and three‐center two‐electron integrals in a symmetrically orthogonalized basis
Author(s) -
Laikov Dimitri N.
Publication year - 2007
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.20485
Subject(s) - basis (linear algebra) , center (category theory) , neglect , mathematics , basis function , electron , mathematical physics , slater integrals , computational chemistry , physics , mathematical analysis , chemistry , geometry , quantum mechanics , psychology , crystallography , psychiatry
A new integral approximation for use in molecular electronic structure calculations is proposed as an alternative to the traditional neglect of diatomic differential overlap models. The similarity between the symmetrically orthogonalized and the original basis functions (assumed orthonormal within each atomic set but nonorthogonal between different centers) is used to construct a robust approximation for the two‐electron integrals, with the error being quadratic in the deviation between the products of the functions. Invariance properties of this procedure are rigorously proved. Numerical studies on a representative set of molecules at valence‐only minimal basis Hartree–Fock level show that the approximation introduces relatively small errors, encouraging its future application in the semiempirical field. © 2006 Wiley Periodicals, Inc. J Comput Chem 28: 698–702, 2007