Spherical-Harmonic Expansion Techniques for Multicenter Integrals over STO’s. A Re-Examination for Vector Processing Computers

Abstract

For calcg. general mol., electron-repulsion, multicenter integrals [MCI's] over STO's that are expressed as spherical-harmonic expansions, algorithms are described. Calcns. of MCI's, done by using new programs with the CRAY-1 vector-processing computer system, showed significant redns. in the computer times required. The products of orbital l-expansions were essentially reduced to several multiplication cycle times. Converge problems still remain for core-like STO's. [on SciFinder(R)]