|
Internet Electronic Journal of Molecular Design - IEJMD, ISSN 1538-6414, CODEN IEJMAT
| ABSTRACT - Internet Electron. J. Mol. Des. November 2004, Volume 3, Number 11, 728-736 |
Convergence Improvement of Two-electron Four-center Coulomb
and Exchange Integrals Over Slater-type Orbitals
Hassan Safouhi and Lilian Berlu
Internet Electron. J. Mol. Des. 2004, 3, 728-736
|
Abstract:
Two-electron four-center Coulomb and exchange integrals the
rate limiting step of ab initio molecular structure calculations.
These integrals contribute to the total energy of the molecule,
which is required to a precision sufficient for small fractional
changes to be evaluated reliably. The Fourier transform method
combined with nonlinear transformations for improving
convergence of highly oscillatory integrals is used to develop an
efficient algorithm for a fast numerical evaluation of molecular
integrals over Slater type orbitals. Numerical results are obtained
for HCN, C2H2, Zn3, BH3,
CH4 and SF6 molecules. They are all
highly accurate and they show that the approach used in this
work, which we previously used for the numerical evaluation of
three-center nuclear attraction, three-center two-electron
Coulomb and hybrid integrals, should lead to a suite of ab initio Slater software.
|