Expansion formulae for two-center charge densities of integer and noninteger n generalized exponential type orbitals applied to evaluation of multicenter multielectron integrals

Abstract

The series expansion formulae in terms of complete orthonormal sets of Ψα-exponential type orbitals introduced by the author are derived for the two-center charge densities of integer and noninteger n generalized exponential functions. The expansion coefficients arising in these relations are the multicenter overlap integrals of three Ψα-functions. The charge density expansion formulae obtained are utilized for the evaluation of multicenter multielectron integrals appearing in the Hartree–Fock–Roothaan and explicitly correlated theories when the generalized exponential type orbitals are employed as basis functions.