ON THE INTERPRETATION OF THE NEXAFS SPECTRUM OF MOLECULAR-OXYGEN

Calculations with extended basis sets and full intrachannel coupling o f discrete and continuum states suggest an alternative interpretation of the NEXAFS spectrum of molecular oxygen. In this interpretation the roles of valence-Rydberg mixing and intrachannel discrete-continuum i nteraction are stressed at the expense of the exchange splitting mecha nism. Calculations indicate that only the doublet-parent channel holds discrete strong transitions with sigma character, while the quartet- parent channel contains preferentially Rydberg-like transitions.