Ionization of excited hydrogenlike ions by collisions with bare ions

Total cross sections have been examined theoretically by using the continuum distorted wave--eikonal initial state (CDW-EIS) and the plane-wave Born approximations for the ionization of hydrogenlike ions in the excited states with the principal quantum number n≤5 in collisions with bare ions in the keV/amu to MeV/amu range. For the ionization of hydrogenlike ions up to C5+(1s) by H+ at low energies, the present CDW-EIS prediction is in good accord with close-coupling calculation, while the Born prediction leads to a considerable overestimate. A comparison is made between the present results and other theoretical predictions as well as experimental measurements