Low-energy single-electron capture cross sections in C6+/C4+ - Na(3s) and N7+/N5+ - Na(3s) collisions: Molecular state approach

The low-energy state-selective capture cross sections for single-electron transfer from the ground state of Na(3s) atoms by fully (C6+ and N7+) and partially stripped (C4+ and N5+) ions have been calculated using the semiclassical approximation in the molecular orbital formulation augmented with the proper electron translation factor. The method of pseudopotential is invoked to account for the interaction of the active electron with the moving nuclei, whose relative motion is considered via a straight-line trajectory. Although both C4+ and N5+ have identical He-like structure, their roles reveal very different collision dynamics. The projectile C4+ exhibits a distinctive role due to its finite core; a low-energy structure in the total capture cross section for C4+ -Na(3s) collisions is observed and explained. For bare projectiles (C6+ and N7+) there remains an increasing tendency of the Stark mixing to characterize the electron transfer processes; it enhances the population of the higher ell states. The ell distribution of the charge-transfer cross section for various projectile is also discussed