The absolute PI cross sections (panels (a), (c) and (e)) from the DARC calculations, and resonance strengths (panels (b), (d) and (f)) from MCDF calculations, as functions of the photon energy (eV) for the Fe16+ (top), Kr26+ (middle) and Xe44+ (bottom) ions

Figure 2. The absolute PI cross sections (panels (a), (c) and (e)) from the DARC calculations, and resonance strengths (panels (b), (d) and (f)) from MCDF calculations, as functions of the photon energy (eV) for the Fe16+ (top), Kr26+ (middle) and Xe44+ (bottom) ions. The photon energies from DARC have been shifted 5.1, 6.7 and 10.85 eV towards the lower energy for Fe16+, Kr26+ and Xe44+, respectively, to match the MCDF calculations. The vertical dotted lines mark the 2snp resonances series obtained by DARC; the vertical lines in panel (b), (d) and (f) give the resonance strength on the resonant positions for 2snp 3P1 (solid diamonds) and 1P1 (6 ≤ n ≤ 13) (hollow diamonds) states of Fe16+, Kr26+ and Xe44+. The dashed lines show the ionization threshold of 2p1/2, 2p3/2 and 2s1/2 states for 2s22p6.

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.