K-shell photoionization of B-like atomic nitrogen ions: experiment and theory

Measurements of absolute cross sections for the K-shell photoionization of B-like atomic nitrogen ions were carried out utilizing the ion–photon merged-beam technique at the SOLEIL synchrotron radiation facility in Saint-Aubin, France. High-resolution spectroscopy with E/ΔE ≈13,500 was the maximum resolution achieved. We have investigated two photon energy regions: 404–409 eV and 439–442 eV. Resonance peaks found in the experimental measured cross sections are compared with theoretical estimates from the multi-configuration Dirac–Fock, R-matrix and empirical methods, allowing identification of the strong 1s → 2p and the weaker 1s → 3p resonances in the observed K-shell spectra of this B-like nitrogen ion. (paper)