# A program system for ab initio MO calculations on vector and parallel processing machines II. SCF closed-shell and open-shell iterations

## Description

Abstract This series of three papers presents a program system for ab initio molecular orbital calculations on vector and parallel computers. Part II is devoted to SCF iterations on closed-shell and open-shell configurations starting from a file of two-electron integrals on the basis of contracted Gaussians (CGTOs). In a preliminary step, the two-electron integrals (pq{norm of matrix}rs) are reordered according to increasing values of index pq = p(p-1)/2+q. Then, in the first SCF iteration step, a fil... Title of program: ASTERIX-SCFCS, ASTERIX-SCFOS Catalogue Id: ABRR_v1_0 Nature of problem Iterative solution of the Schrodinger equation for molecules in the Restricted Hartree-Fock approximation, using the formalism developed by Roothaan for closed-shell and open-shell configurations. Versions of this program held in the CPC repository in Mendeley Data ABRR_v1_0; ASTERIX-SCFCS, ASTERIX-SCFOS; 10.1016/0010-4655(90)90082-C This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018)