Diagrammatic perturbation theory: the importance of f basis functions in molecular electron correlation energy calculations

Abstract

The importance of basis functions with f symmetry in diagrammatic many-body perturbation theory calculations of molecular electron correlation energies is investigated. Calculations are reported for the carbon monoxide molecule using two basis sets, the first containing functions of s, p and d symmetry and the second containing functions of s, p, d and f symmetry. The dependence of the component of the correlation energy which is associated with basis functions of f symmetry on the internuclear distance is examined.