Autoionization of O2 by photoelectron spectroscopy

Photoelectron spectra of molecular oxygen have been studied at photon wavelengths of 736, 744 and 584 Angstroem, respectively. The reported strong perturbation at 736 Angstroem leading to changes in the normal vibrational intensities of the X2 PIsub(g) and α4PIsub(u) states is ascribed to autoionization from a very wide, near-repulsive state of the neutral molecule. The values measured for the relative vibrational intensities of the ionic states are compared with the latest experimental results available in the literature. (orig.)