Comparison of one and two centre studies of low energy scattering by diatomic molecules

Abstract

The elastic, momentum transfer and rotational excitation cross sections for low energy positrons scattered by hydrogen molecules are calculated using respectively, spherical and spheroidal coordinates and harmonic expansions. Both the spherical and the spheroidal calculations are done in the adiabatic-nuclei approximation. The harmonic expansions in the two coordinate systems are both truncated at corresponding order (up to and including d-waves). The calculations are identical, save for the fact that partial spherical analysis is used in one case and partial spheroidal analysis in the other. The two sets of results so obtained turn out to be almost identical.