In order to evaluate the Coulomb and exchange integrals in the semiempirical SCF MO methods over an spd-basis of orbitals, an approximation of the model function of the Coulomb hole is used. The procedure of calculating mono-and bicentric Coulomb integrals based on the properties of Fourier transfor
An approximation of the two-center coulomb integrals in the semiempirical LCAO-MO methods
โ Scribed by N. Tyutyulkov; A. Gochev; F. Fratev
- Publisher
- Elsevier Science
- Year
- 1969
- Tongue
- English
- Weight
- 151 KB
- Volume
- 4
- Category
- Article
- ISSN
- 0009-2614
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โฆ Synopsis
It is shown that the singlet and triplet transition energies of hydrocarbons may be calculated by means of the generalised Mataga-Nishimoto approximation for the two-center Coulomb integrals.
๐ SIMILAR VOLUMES
The suggestion is made that the storage of long lists of two-election repulsion integrals in the LCAO SCF MO merhod could be avoided if such integrals were evaluated at each SCF cycle and an initial set of eigcnvectors were available to lead to rapid convergkncc.'Rcsults are presented showing that t
Three-center nuclear attraction and four-center two-electron Coulomb integrals over Slater-type orbitals are required for ab initio and density functional theory (DFT) molecular structure calculations. They occur in many millions of terms, even for small molecules and require rapid and accurate eval