Electron spectra from singlet and triplet states of O⁴⁺(1s²3l3l', 1s²3l4l') produced by 60 and 120 keV O⁶⁺+He, Ne, Ar collisions

Abstract

Ejected electrons from the singlet and triplet states of doubly excited O4+ (1s23l3l') and O4+ (1s23l4l') ions, produced by 60 and 120 keV O6+ (1s2) 1S+X collisions (X identical to He, Ne, Ar), have been measured with high resolution zero-degree electron spectroscopy. Only the singlet states were observed when He gas was the target. In contrast, mainly triplet states were observed when Ne gas was used. Both singlet and triplet states contributed to the electron spectra, produced by O6+ (1s2) 1S+Ar collisions. Two theoretical methods, perturbation theory or Z-expansion (MZ code) and multiconfigurational Hartree-Fock (Cowan code) were used for identification of ejected-electron spectra. The contribution of correlation effects is discussed by comparison with other theoretical energies.