A high-resolution N 1s photoionization study of the molecule in the near-threshold region

The angle-resolved N 1s photoelectron spectrum of N2 has been measured with high resolution in the threshold region. An analysis of the vibrational fine structure yields a vibrational energy of 314(4) meV and a lifetime broadening of 103(10) meV for the core-ionized molecule. As in the case of C 1s ionization of CO, the vibrational fine structure changes considerably with photon energy in the region of both the sigma* shape resonance and the double excitations. Both the vibrationally resolved partial photoionization cross sections and asymmetry parameters have been determined in this photon energy range. The calculated cross sections in the literature are in reasonable agreement with experiment. In addition, we have measured the cross sections and asymmetry parameters of the most intense direct and conjugate shake-up satellites. The behaviour of the pi-pi* satellites is found to differ significantly from that of the corresponding C 1s satellites of CO.