ELECTRON-EXCITATION OF HYDROGENIC TARGETS IN COLLISIONS WITH IONS OR ATOMS

A symmetric eikonal model is developed to study electron excitation of hydrogenic atoms by impact of heavy ions (composed of a nucleus and N electrons) at intermediate and high collision velocities. Differential cross sections are calculated for impact of He+ ions on H targets and compared with existing experimental data for formation of H(n = 2) atoms. Total cross sections for collisions of singly (H+, He+, Li+) and doubly charged (He2+, Li2+) projectiles on H targets are also computed. A good representation of measurements is obtained for He+ ions. The role played by the spatial distribution of projectile electrons is analysed.