Screening effects for excitation probabilities in ion-atom collisions

Transition probabilities for 1s-2s, 1s-2p and 2s-2p excitations due to the Coulomb interaction of a structureless projectile with a target atom or ion are derived in the first-order semi-classical approximation. Screened hydrogenic wave functions are used for the target electron, with the screening parameters determined through a self-consistent minimization of the total binding energy of the target atom. A straight line trajectory is assumed for the projectile. Analytic expressions are derived for the transition probabilities and compared with previous work by other authors. (orig.)