Vibrationally resolved photoionization of the 1σg and 1σu shells of N2 molecule

Theoretical and experimental study of vibrationally resolved partial photoionization cross sections and angular asymmetry parameter β for the 1σg and 1σu shells of N2 molecule in the region of the σ* shape resonance is reported. The measurements were made at the synchrotron radiation facility SPring-8 in Japan. The calculations in the random phase approximation have been performed using the relaxed core Hartree–Fock wavefunctions with the fractional charge of the ion core equal to 0.7. With its help, the role of interchannel coupling between the closely spaced 1σg and 1σu shells was studied. The experiment demonstrates the existence of a correlational maximum in the 1σu shell photoionization cross section induced by the σ* shape resonance in the 1σg shell. This maximum reveals itself even more clearly in the angular asymmetry parameter β for the v' = 0 and v' = 1 vibrational states of the ion. The calculation in the random phase approximation gives a consistent interpretation of the experimental data.