A study of the partial photoionization cross sections of the N2 valence-shell states

The vibrationally resolved partial ionization cross sections of the X, A and B states of N2+ in the photon energy range ~20-35 eV have been characterized by photoelectron spectroscopy. Vibrational intensity ratios of the X, A and B states have been determined. The vibrational intensity ratios of the X and B states show a wealth of both sharp and broad features. In accordance with previous experimental and theoretical studies, these structures have been assigned either to one-electron processes, like the interchannel coupling between the 3?g and 2?u ionization channels and the autoionization of excited Rydberg states, or to two-electron processes, like the recently observed non-Rydberg doubly excited resonances (NRDER). The present study provides direct information on the autoionization of the NRDER states and the experimental evidence of their predicted, but not yet verified, selective decay to the X, A and B states of N2+.