Comparison of PI cross sections between the present results and the available theoretical and experimental data for Ar8+
Figure 1. Comparison of PI cross sections between the present results and the available theoretical and experimental data for Ar8+. (a) Our results from DARC; (b) the convoluted results of DARC (black line), our MCDF results (blue vertical lines with circles), and those calculated by Simon et al (red vertical lines with diamonds) using a Gaussian profile of FWHM = 800 meV, and the results from TOPbase  (magenta dotted line) convoluted with FWHM = 300 meV; (c) overview of experimental PI spectrum of the Ar8+ ion .
Photoionization (PI) cross sections of the ground state 1s2 2s2 2p61 S0 of Ne-like Ar8+, Fe16+, Kr26+ and Xe44+ ions are calculated by using the Dirac atomic R-matrix code based on a fully relativistic R-matrix method. To analyze the detailed resonant structure, systematical calculations based on the multiconfiguration Dirac–Fock method are performed for the dominant 2s → np resonant transitions, and the resonant energies, strengths and total natural widths are presented. The resonant structures and characteristics of the PI cross sections and resonance strengths along the Ne-like sequence are discussed with emphasis on the influence of relativistic effects. For the Ar8+ ion, good agreement is found between the present results and available theoretical calculations and experimental data.