REGULARIZATION METHOD AND MOLECULAR INTEGRALS WITH SINGULAR EXPONENTIAL FUNCTIONS

The regularization principle, which is based on the concept of linearl y independent singular functions, makes it possible to calculate many important types of molecular matrix elements arising in the variationa l LCAO-MO-SCF scheme. This is done using a direct approach that employ s reduction of these elements to finite sums of convergent and diverge nt one-electron integrals. A universal algorithm is developed to calcu late two-center one-electron molecular integrals involving both singul ar and ordinary Slater functions. The numerical stability of the algor ithms and the accuracy of the integral calculation are analyzed, and n umerical estimates are given.