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 C2+ ion leading to the C3+ 2l and 3l(l = 0, 1) states from the 1S ground state have been calculated. The lower members of all autoionizing Rydberg series converging to the C3+ 2p, 3s, 3p, and 3d thresholds are identified and their energies and widths are determined. Except for the resonances converging to the C3+ 2p threshold, all of the resonance series are perturbed by overlapping series converging to other thresholds. In addition, the 4s4p 1P resonance is found to lie just below the C3+ 3d threshold. The calculations show excellent agreement between length and velocity gauges. Comparison with experiment for the photoionization of a mixture of the 1S ground state and 3P metastable states of C2+ 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.