The O 1s -> sigma* Resonance on O2: Inadequacy of Only Two Exchange-Split Components

The O 1s→σ* transition below the O K-edge in O2 has been investigated by absorption, constant ionic state (CIS) experiments, and extensive configuration interaction calculations. CIS scans of the three lowest-lying final states reached in resonant Auger decay provide a wealth of information on energy range, symmetry, and spin multiplicity of the intermediate states with σ* character. We conclude that the identification of only two exchange-split components is inadequate because a complex manifold of states with σ* character exists with no unique energy difference between related states