Collisions of Atoms with Highly Charged Ions: General Theoretical Description

Abstract

The theoretical description of ion-atom or ion-ion collision processes is more complex than that of radiative and electron-ion collision processes due to the fact that, besides the electronic motion, the relative motion of the nuclei should also be adequately described. Moreover, during the collision, the electronic and nuclear motions are mutually coupled, and this introduces new aspects in the collision dynamics. Since the colliding system is, in general, a multielectron system, the number of inelastic processes that can occur is fairly large, and includes target excitation or ionization, electron capture, simultaneous capture and excitation (or ionization), and other processes involving one- or many-electron transitions. The theoretical descriptions of most of these processes differ and depend on the collision energy. However, many of them can be described by unifying theoretical approaches, and the specific features of each particular process appear only in the latter stages of the treatment.