Photoionization of the ground state of the Be-like C²⁺ ion leading to C³⁺ 2l and 3l states

Abstract

Total and partial photoionization cross sections of the Be-like C 2+ ion leading to the C 3+ 2l and 3l (l = 0, 1) states from the 1 S ground state have been calculated. The lower members of all autoionizing Rydberg series converging to the C 3+ 2p, 3s, 3p, and 3d thresholds are identified and their energies and widths are determined. Except for the resonances converging to the C 3+ 2p threshold, all of the resonance series are perturbed by overlapping series converging to other thresholds. In addition, the 4s4p 1 P resonance is found to lie just below the C 3+ 3d threshold. The calculations show excellent agreement between length and velocity gauges. Comparison with experiment for the photoionization of a mixture of the 1 S ground state and 3 P metastable states of C 2+ in the photon energy range 40.8-56.9 eV shows good agreement with the present theoretical results; for the comparison, a calculation of photoionization of the metastable state was also performed. The present calculations are also compared with other previous theoretical and experimental results.

Photoionization of the Be isoelectronic sequence: total cross sections

“…Several photoionization calculation of lower members of the isoelectronic sequence, Be [23,24], B + [25,26], and C +2 [27,28], have been calculated for both ground and metastable states using a variational R-matrix method (VRM) [41]. In these calculations, the 1s 2 core is replaced There have also been calculations of the photoionization of C +2 [29,30], N +3 [30] and O +4 [31] using orbitals obtained with the SUPERSTRUCTURE code [42] and nonrelativistic R-matrix to calculate the cross sections, except for C +2 where a relativistic calculation was also done.…”

“…Extant experimental measurements include Be [15,16], B + [17], C +2 [18], N +3 [19,20], and O +4 [21]. Previous calculations include, in addition to Opacity Project [11,22], work on Be [23,24], B + [25,26], C +2 [27][28][29], N +3 [30], and O +4 [31].…”

“…Opacity Project [11,22], work on Be [23,24], B + [25,26], C +2 [27][28][29], N +3 [30], and O +4 [31].…”

Photoionization Study on the 1s\(^{2}\)2snp \(^{1}\)P\(^\circ\), 1s\(^2\)2snd \(^{1,3}\)D, and 1s\(^{2}\)2pnd \(^{3}\)D, Rydberg Series of the Be-like \((Z=8-18)\) ions

“…For the 2s8d 3 D and 2s9d 3 D levels, the SCUNC quantum defects as quoted in Table 8 are constant and equal to 0.033. For the same levels, the corresponding NIST quantum defects evaluated from the standard formula (7) are equal to 0.027 for 2s8d 3 D and 0.180 for 2s9d 3 D.…”

“…On the experimental side, previous measurements have been performed on Be atoms [22] and Be-like ions, such as B + [19], C 2+ [14], N 3+ and O 4+ [3]. In addition, calculations on the Be-like sequences with Z = 6 − 10 have been performed [5,[7][8][9][10][11][12] using a non-iterative variational R-matrix method. The R-matrix approach has also been applied to report resonance energies and widths of the 2pns 1 P • and 2pnd 1 P • Rydberg series of O 4+ (n = 6 − 10) [6], F 5+ (n = 6 − 10) [5] and Ne 6+ (n = 7−9) ions [4].…”