Ejected-electron spectra from the triplet states of O4+(1s23l3l') produced by O6++O2collisions

Ejected electrons from the triplet states of doubly excited O4+ ions, produced by 60 keV O6++O2 collisions, have been measured with high resolution zero-degree electron spectroscopy. The triplet states of doubly excited configurations are selectively produced through double electron transfer processes with the O2 molecular target under single collision conditions. Electrons ejected from the 1s22pnl and 1s23lnl' configurations are observed over a wide energy range. Ejected-electron spectra from the O4+(1s23l3l') are compared with theoretical calculations. The calculation of energy levels of 1s23l3l' states has been carried out by the Z-expansion method, where Z is the nuclear charge. Correlation, relativistic and radiative effects are taken into account. Electrons from triplet states are identified by comparison with the calculations and the 'singlet state' spectrum produced by O6++He collisions.