State-selective charge transfer in slow collisions of O3+ with H and H-2

We have used photon emission spectroscopy to determine absolute, state-selective cross sections for single-electron capture by O3+ ions colliding on atomic and molecular hydrogen. The impact energy was varied between 45 and 752 eV amu(-1). For O3+ + H collisions we find that the cross section for capture into the 2p3s state of O2+ strongly increases with impact energy up to an energy of approximate to 100 eV amu(-1). At higher impact energies the 2p3s cross section becomes comparable to the more or less constant 2p3p cross section. For the O3+ + H-2 system these state-selective cross sections both stay approximately constant over the entire energy range investigated. Our results will be compared with existing experimental and theoretical data