Fine structure energies (in eV) of Ar⁹⁺, Fe¹⁷⁺, Kr²⁷⁺ and Xe⁴⁵⁺ target ions

<b>Table 1.</b> Fine structure energies (in eV) of Ar⁹⁺, Fe¹⁷⁺, Kr²⁷⁺ and Xe⁴⁵⁺ target ions. <strong>Abstract</strong> 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 <em>R</em>-matrix code based on a fully relativistic <em>R</em>-matrix method. To analyze the detailed resonant structure, systematical calculations based on the multiconfiguration Dirac–Fock method are performed for the dominant 2s → <em>n</em>p 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.