State-selective electron capture by 2-8 keV O2+ recoil ions in H, H2 and He

Abstract

Translational energy spectroscopy has been used with slow O2+ ions from a recoil source to study state-selective electron capture by 2-8 keV O2+ ions in H, H2 and He. As in the authors' previous work a furnace target configuration was used for measurements in atomic hydrogen. The main excited product channels have been identified and their relative importance has been assessed. The presence of 1D metastable primary O2+ ions is evident in the measurements in H and H2. Electron capture by ground-state 3P primary ions is dominated by 2p electron capture in all cases together with projectile core excitation in targets of H and H2. Multichannel Landau-Zener calculations have been applied to the O2+/He system but, like previous quantal calculations, these fail to correctly explain their observations.