Simultaneous electron capture and target ion excitation in collisions of C4+ and N5+ on He

Cross sections for simultaneous electron capture and target ion excitation have been measured for impact of slow He-like C4+ and N5+ ions on He. The energy of the primary ion beams has been varied over more than two orders of magnitude: 0.05-7 keV/amu. The results are discussed on basis of a slightly modified version of the ''dynamic'' classical over-barrier model for multiple electron capture. The differences in the energy dependences of the experimental results of C4+ and N5+ - He can be explained qualitatively by assuming that for N5+ binding energy sharing between the two participating electrons is of importance, particularly at the lower impact energies.