Theory of positronium-atom scattering

Abstract

This survey reports theoretical studies involving positronium-atom scattering. Investigations carried out on the interaction of positronium (Ps) atoms in gases during the last three decades have been briefly reviewed in this article. The recent studies using the Ps close coupling method form a part of the present resume. The partial wave theory using the close coupling method in which both the atoms are allowed to be excited to non-zero orbital angular momentum states has been presented. This article advocates the need to include the effect of exchange and to retain the excited states of both the atoms to predict reliable results.