Theory of ionization processes in positron-atom collisions

Abstract

We review past and present theoretical developments in the description of ionization processes in positron-atom collisions. Starting from an analysis that incorporates all the interactions in the final state on an equal footing and keeps an exact account of the few-body kinematics, we perform a critical comparison of different approximations, and how they affect the evaluation of the ionization cross section. Finally, we describe the appearance of fingerprints of capture to the continuum, saddle-point and other kinematical mechanisms. © 2006 Elsevier B.V. All rights reserved.