X-ray absorption and resonant Auger spectroscopy of O(2) in the vicinity of the O 1s-->sigma(*) resonance: Experiment and theory.
We report on an experimental and theoretical investigation of x-ray absorption and resonant Auger electron spectra of gas phase O(2) recorded in the vicinity of the O 1s-->sigma(*) excitation region. Our investigation shows that core excitation takes place in a region with multiple crossings of potential energy curves of the excited states. We find a complete breakdown of the diabatic picture for
