Ab initio SCF calculations on [V10O28]6−: A benchmark for the classical calculation and processing of molecular integrals on large Gaussian basis sets

A vector efficient implementation of the McMurchie and Davidson algorithm for the calculation of one‐ and two‐electron molecular integrals is presented, as available in the Cray version of the ASTERIX program system. The implementation and performance of a vector‐oriented strategy for the generation and processing of the P supermatrix is also discussed. This program system has been applied to the ab initio SCF computation of the ground‐state wave function for the [V10O28]6− ion, with a basis set of triple‐zeta quality for the valence shell of oxygen generating 1404 GTOS and 574 CGTOS for the complete system. The performance and the bottlenecks of the integral calculation are discussed as a function of the integral classes. Two‐dimensional maps of the electrostatic potential are presented for this molecule and compared to experimental information about proton fixation.