Theoretical calculations of cross sections for electron capture in collisions of proton with He+ and Li++ ions at high energies

We have computed the partial cross section ratios of electron capture into excited states to ground state in collisions of proton with He+ and Li++ ions using Oppenheimer-Brinkman-Kramers and continuum-distorted-wave methods. Our results show that the cross section ratios obtained by the two different methods are consistent with each other at high energies. Consequently, we propose a simple method to estimate the partial and total cross sections of electron capture by proton from any hydrogen-like ions at high energies.