δ-function model potential for the calculation of pair correlation energies in atoms

Abstract

Pair correlation energies for first‐row atoms are calculated using an attractive δ‐function potential and the original Slater orbitals. This model potential is the simplest short‐range attractive pair potential and several semiquantitative results can be easily derived using it. Analogs of Hund's rules are applied to pair correlation energies. The model distinguishes between transferable and nontransferable pairs and is able to account for the Z (nuclear charge) dependence of the nontransferable pairs quite well. It does not reproduce the dependence of the nontransferable pairs on N (the number of electrons) accurately because this dependence involves all of the electrons in the shell and so cannot be treated by means of a simple pair model involving only one pair of electrons.