Sk. Ignatov et al., SEMIEMPIRICAL CALCULATION OF 2-ELECTRON INTEGRALS USING BIPOLAR EXPANSION OF THE OHNO POTENTIAL, Journal of structural chemistry, 36(4), 1995, pp. 538-543
Bipolar expansion of the Ohno potential as a method of calculating two
-center Coulomb integrals that appear in the NDDD approximation is gen
eralized to one-center two-electron integrals. A unified semiempirical
scheme is suggested for estimating two-electron interactions in molec
ules. This scheme can be readily extended to arbitrary Slater basis se
ts (including the s,p,d-orbitals) and involves no a priori data on the
valent states of atoms. lit this work, the scheme is employed to exte
nd the semiempirical PM3 method to the s,p,d-basis set. The efficiency
of the method is proven by test calculations of 24 chromium compounds
(pi-complexes, carbonyls, isocyanides, etc.).