THEORY OF RELATIVISTIC ION-ATOM COLLISIONS

Ion-atom collisions at relativistic beam energies constitute a new field of systematic experimental and theoretical studies. With the aid of sufficiently energetic heavy-ion beams, high stages of ionisation, including bare uranium nuclei, can be achieved, and these previously unavailable species can be used for further studies. Moreover, a wealth of collision phenomena can be studied either for their own theoretical interest, or as a way to produce highly stripped ions in specific states. In this review, we give a largely self-contained introduction to some general features of relativistic heavy-ion collisions and then proceed to a theoretical description of ionisation, of charge exchange, of a simultaneous treatment of excitation and charge transfer by the coupled-channel method, of radiative electron capture, and finally of electron-positron pair production. For all processes described, various theoretical approaches and their possible limitations are examined, comparison is made with existing experimental data, and attention is paid to the limit of extreme-relativistic collision energies. © 1990.