Absolute state selective cross sections for ionization-excitation of helium in fast H+ + He and C6+ + He collisions: Zp-dependence

Abstract

Absolute EUV emission cross sections for simultaneous ionization and excitation of helium by H+ and C6+ projectiles have been measured for impact energies between 0.83 and 2.3 MeV/u. In this energy range the mass, charge and velocity dependence of the ionization-excitation cross sections is compared for the He+(np) Rydberg states forn≤5. It is found that the experimental cross sections vary approximately asZ p 3 .