Molecular-frame photoelectron angular distributions in inner-valence photoionization of N₂

A full partial-wave analysis of photoionization to two inner-valence states of N₂⁺ has been achieved on the basis of experimental molecular-frame photoelectron angular distributions determined by the velocity imaging photoionization coincidence (VIPCO) technique. The two states (2σ_g)^{-1 2}Σ_g⁺ and F ²Σ_g⁺ are assumed to dissociate rapidly so that the axial recoil approximation applies. The dipole matrix elements and phase shift differences show the strong influence of the known shape resonance, and are in reasonable agreement with some existing theoretical predictions.