Shorter Expansions of Molecular Integrals in Hylleraas-CI Calculations

Abstract

Over Cartesian Gaussian orbitals, Clementi and his co–workers have recently derived the formulas of molecular integrals appearing in the Hylleraas–CI method. There are many terms which exactly cancel one another in their formulas. By using the approach of generating functions, these terms are removed, giving rise to shorter expansions and simpler expressions for the molecular integrals.