Electron transfer, ionization, and direct excitation in collisions between protons and highly charged hydrogenic ions from N⁶⁺ to S¹⁵⁺

With the first Born approximation, Oppenheimer in 1928 was the first to treat Electron transfer in p-H(1s) collisions. Beginning in the 1960's, collisions have also been considered using various non-perturbative, coupled-state approaches, as well as second-order perturbation theory. In view of the high asymmetry of the collisional systems considered here, the

chosen bases consist of many functions (specifically, many Sturmian functions) centered on the target nucleus, but just a single $1s$ function centered on the proton. The extent to which simple scaling rules with target nuclear charge $Z$ are valid---rules from perturbation theory---is being examined for ionization and electron transfer, and particularly for direct excitation, at intermediate energies near where the cross sections peak, as well as at higher energies. The present work extends that for $Z\le6$.

T. G. Winter, Phys. Rev. A 87, 032704 (2013)