CALCULATION OF MULTICENTER ELECTRON REPULSION INTEGRALS IN SLATER-TYPE BASIS-SETS USING THE SIGMA-SEPARATION METHOD

The application of the Sigma-separation method to the calculation of multicenter two-electron molecular integrals with Slater-type basis functions is reported. The approach is based on the approximation of a scalar component of the two-center atomic density by a two-center expansion over Slater-type functions. A least-squares fit was used to determine the coefficients of the expansion. The angular multipliers of the atomic density were treated exactly. It is shown that this approach can serve as a sufficiently accurate and fast algorithm for the calculation of multicenter two-electron molecular integrals with Slater-type basis functions. (C) 1995 John Wiley and Sons, Inc.