Plane-wave Born treatment of projectile-electron excitation and loss in relativistic collisions with atomic targets

Electron excitation and loss of relativistic ion projectiles colliding with atomic targets are studied within the framework of the first order of the plane-wave Born approximation. General expressions are derived for the elastic and electron-electron contributions to the electron excitation and loss cross sections. In the limit of nonrelativistic collision velocities these expressions go over into known nonrelativistic formulas. In ultrarelativistic collisions shielding effects are shown to be very important for the excitation and loss cross sections even for collisions of highly charged projectiles with light atomic targets. Results of our calculations for the electron loss cross sections are in reasonable agreement with available experimental data on projectile-electron loss in relativistic collisions.