Electron capture in an arbitrary excited s state by proton passing through hydrogenic ions

The Coulomb-Born approximation has been used to calculate the charge-transfer cross section for the non-symmetric process, H + + Z A X (Z-1)+ to H*(ns)+ Z A X Z+ in the energy range 50-400 keV, where the electron may be captured in any arbitrary excited s state. The asymptotic form of the cross section as n to infinity has also been presented. Cross sections for the above process with n=2, 3, 4, 5, infinity , and for the target ions 4 He + , 6 Li 2+ and 12 C 5+ have been calculated.