K-Shell Photoionization of Singly Ionized Atomic Nitrogen: Experiment and Theory

TL;DR

This study combines high-resolution experimental measurements and advanced theoretical calculations to analyze K-shell photoionization of singly ionized nitrogen, revealing detailed resonance features in the spectra.

Contribution

It provides the first high-resolution experimental data for nitrogen ion K-shell photoionization and compares it with state-of-the-art theoretical models, enhancing understanding of atomic processes.

Findings

Identification of strong 1s → 2p resonances

Agreement between experiment and MCDF and R-matrix calculations

Precise resonance energies and cross sections obtained

Abstract

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/$\Delta$E $\approx$ 7,000 was achieved with the photon energy from 388 to 430 eV scanned with a band pass of 300 meV, and the 399.4 to 402 eV range with 60 meV. Experimental results are compared with theoretical predictions made from the multi-configuration Dirac-Fock (MCDF) and R-matrix methods. The interplay between experiment and theory enabled the identification and characterization of the strong 1s $\rightarrow$ 2p resonances observed in the spectra.