He2+-He collisions: one-electron capture and target-ion excitation

By means of photon emission spectroscopy we have studied state selective one-electron capture and target-ion excitation in collisions of He-2+ with He. The collision energy has been varied from 1 to 75 keV amu-1 Four-body classical trajectory Monte Carlo calculations have been performed in the energy range of 50-300 keV amu-1. In the energy range where experiment and theory overlap there is in general fair agreement, although the 1-distributions within a principal quantum shell exhibit differences. At energies below 50 keV amu-1 the experiments confirm the results of atomic orbital calculations, presented in an accompanying paper by Fritsch. Combining all the experimental and theoretical data we have determined a reliable cross section data base for use in neutral helium beam based plasma diagnostics on large tokamaks.