CHARGE-EXCHANGE IN ENERGETIC ION-ATOM COLLISIONS

An overview of the current status of perturbative theoretical approaches to charge exchange in energetic ion-atom collisions is presented. One of the main aims of the article is to provide a critical assessment of various theoretical models by pointing out their advantages and shortcomings and, in some cases, by clarifying misunderstandings. To furnish a theoretical frame, a discussion of three-body collisions for short-range interactions as well as for long-range Coulomb interactions is given. Particular emphasis is placed on the importance of satisfying the Coulomb boundary conditions. The boundary-corrected perturbation formalism and its applications are discussed in some detail. Related distorted-wave models and various multiple-scattering approaches, including the continuum distorted wave (CDW) model, are also discussed. The high-energy behaviour of charge exchange cross sections is reviewed. A number of illustrative comparisons between theory and experiment are presented.