Autoionisation of superexcited states to the N2+ B state in N2

Vibrationally resolved N2+ (B-X) (1-2) and (0-1) emission bands were recorded after photoexcitation of N2 in the 20-46 eV energy range. The branching ratio between these transitions reveals strong non-Franck-Condon effects. Ab initio calculations using a configuration interaction method based on Kohn-Sham orbitals indicate that the autoionisation of certain superexcited states is responsible for some structures present in the branching ratio curve.