Generalization of atomic random-phase-approximation method for diatomic molecules. II.N2K-shell photoionization

Abstract

Partial and total photoionization cross sections of the K shell of the ${\mathrm{N}}_{2}$ molecule are calculated using the generalization of the random-phase approximation that has been applied earlier to the valence shells of ${\mathrm{N}}_{2}$ [Phys. Rev. A 61, 032704 (2000)]. At zero order the relaxed core Hartree-Fock approximation is used. It is demonstrated that due to strong intershell correlations the $\ensuremath{\sigma}*$ shape resonance reveals itself not only in the $1{\ensuremath{\sigma}}_{g}\ensuremath{\rightarrow}\ensuremath{\epsilon}{\ensuremath{\sigma}}_{u}$ channel as it takes place in all single-particle approximations, but also in the $1{\ensuremath{\sigma}}_{u}\ensuremath{\rightarrow}\ensuremath{\epsilon}{\ensuremath{\sigma}}_{g}$ channel. The influence of vibrational motion on the cross sections is taken into account. Good agreement with the most recent experimental data for different partial cross sections is achieved.