The 2s<em>n</em>p threshold energy (<em>E</em>_limit) and quantum defect δ of ³P₁ and ¹P₁ states of Ar⁸⁺, Fe¹⁶⁺, Kr²⁶⁺ and Xe⁴⁴⁺ ions

Table 5. The 2snp threshold energy (Elimit) and quantum defect δ of 3P1 and 1P1 states of Ar8+, Fe16+, Kr26+ and Xe44+ ions. Abstract 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.