Dynamics of ionization in atomic collisions

The present state of the theoretical study of ionization in ion–atom and atom–atom collisions is reviewed on the basis of quantum mechanical approaches to the solution of the time-dependent Schrödinger equation. Perturbative theories as well as the methods employing exact numerical solutions of the Schrödinger equation, expansion of wave functions on atomic and molecular bases and Sturmian expansions are considered. Advantages and limitations of these methods are assessed for colliding systems with one “active” electron, e.g. H+–H and He2+–H. Comparison of calculations with available experimental data is given in a broad collision energy range. Perspectives for further developments are discussed.