MP2 energy evaluation by direct methods

Abstract

An efficient algorithm is presented for evaluating the second-order Møller-Plesset (MP2) energy directly from two-electron integrals in the atomic orbital basis, i.e. the integrals are not stored. The floating point operation count and memory requirements are analyzed, and illustrative calculations are presented. This direct MP2 method should be useful for large molecule calculations, where, due to storage limitations, conventional disk-based MP2 procedures are often not feasible. © 1988.