Relativistic cross sections of electron-impact ionization of hydrogenic ions.

Relativistic total and single-differential cross sections of positron-impact ionization are calculated for the hydrogen atom and hydrogenlike ions for incident positron energies up to 10 times the ionization energy. Two different sets of distorting potentials are used to study the mutual screening of the outgoing positron and electron. Relativistic effects are investigated by taking the nonrelativistic limit. Results are compared with available theoretical and experimental data.