Theory of projectile-electron excitation and loss in relativistic collisions with atoms

We review the recent progress in the theory of relativistic ion–atom collisions where the projectile-ion initially carries active electrons. We present a detailed discussion of quantum and semiclassical first-order theories for the projectile-electron excitation and loss in relativistic collisions with neutral atomic targets. The influence of the higher-order terms in the projectile–target interaction on the projectile-electron excitation and loss in ultrarelativistic collisions is considered by using the ‘light-cone’ approximation. eories discussed are applied to study (i) excitation and loss probabilities as functions of the collision impact parameter and (ii) excitation and loss cross sections. Calculations for cross sections are compared with experimental data.