Decomposition of the photoabsorption Schumann-Runge continuum in O₂

The photoabsorption Schumann-Runge continuum in O 2 has been decomposed into the contribution from states of both valence and Rydberg character. The decomposition of the experimental photoabsorption (or high-energy, zero-angle, electron energy-loss) data contains contributions from three valence states, four Rydberg states, and one state of unknown character. Information on the perturbed valence-state potential-energy curves in the Franck-Condon region obtained by this analysis substantiate theoretical conclusions of strong valence-Rydberg perturbations in the 8-12 eV excitation region. There is presently no unambiguous identification for the state at 8.93+or-0.04 eV, found in the optical and all the electron energy-loss data.