A NEW SINGLE-CENTER METHOD TO COMPUTE MOLECULAR INTEGRALS OF QUANTUM-CHEMISTRY IN SLATER-TYPE ORBITAL BASIS OF FUNCTIONS

The present work is dedicated to the introduction of a new single-center expansion method derived from the Barnett and Coulson approach leading to reliable numerical algorithms. The basic concept lies in the use of the integral representations of the modified Bessel functions I(LAMBDA+1/2) and K(LAMBDA+1/2), rather than employing their closed analytical expressions that are known to involve large numbers that usually make the numerical calculation worthless. It is applied to two-center overlap and Coulomb integrals as well as to three-center nuclear attraction integrals useful in density functional theory. (C) 1994 John Wiley & Sons, Inc.