Adiabatic theory for binary-encounter-electron emission

The electron-impact approximation for the ejection of target electrons by heavy, highly charged projectiles is modified in order to allow for a distortion of the initial state by the heavy perturber. Model calculations for ionization of H₂ by 0.5–0.6 MeV/amu Cu⁵⁺ impact show that the binary-encounter peak is considerably broadened when distortion effects are included. In general, this leads to a better agreement of the peak shape with experimental data than the conventional binary-encounter model.