Electronic decay of core hole excited states in molecular oxygen.

Electron energy spectra characterizing the relaxation of molecular oxygen from different core hole excited states are reported. By using monochromatic synchrotron radiation, spectra are obtained with excitation at the π* and σ* resonances and at various energies above the ionization threshold. The spectra obtained with excitation above threshold are very similar and result from Auger decay. The spectra obtained at the σ* resonance result from spectator autoionization, and those for the π* resonance result from both spectator and participator autoionization. The σ* resonance is broadened by spectral congestion, and the autoionization spectra indicate the presence of three components. Configurations and states produced by the electronic decay are identified, and a correlation between spectator screening and term values is documented. [ABSTRACT FROM AUTHOR]