K-shell photoionization of singly ionized atomic nitrogen: experiment and theory

Absolute cross sections for the K-shell photoionization of C-like nitrogen ions were measured by employing the ion‐photon merged-beam technique at the SOLEIL synchrotron radiation facility in Saint‐Aubin, France. High-resolution spectroscopy with E/! E ! 7000 was achieved with the photon energy from 388 to 430 eV scanned with a band pass of 300 meV, and the 399.4‐402 eV range with 60 meV. Experimental results are compared with theoretical predictions made from the multi-configuration Dirac‐Fock and R-matrix methods. The interplay between experiment and theory enabled the identification and characterization of the strong 1s " 2p resonances observed in the spectra. (Some figures in this article are in colour only in the electronic version)