Optimal damping algorithm for unrestricted Hartree-Fock calculations

TL;DR

This paper introduces optimal damping algorithms for unrestricted Hartree-Fock calculations, improving convergence efficiency in open-shell molecular systems through new equations and testing their performance.

Contribution

The paper presents novel optimal damping algorithms for UHF calculations, with derived equations for both concurrent and alternate Fock matrix constructions, enhancing convergence.

Findings

Concurrent algorithm outperforms alternate in convergence speed

Test calculations confirm improved performance of the proposed algorithms

Algorithms are applicable to open-shell molecular systems

Abstract

We have developed a couple of optimal damping algorithms (ODAs) for unrestricted Hartree-Fock (UHF) calculations of open-shell molecular systems. A series of equations were derived for both concurrent and alternate constructions of alpha- and beta-Fock matrices in the integral-direct self-consistent-field (SCF) procedure. Several test calculations were performed to check the convergence behaviors. It was shown that the concurrent algorithm provides better performance than does the alternate one.