Characteristics of photoionization in the XUV domain for the excited 1s22s2p1,3Po states of the Be-like C2+ ion

Abstract

Resonance structures and their characteristics in the photoionization of the first excited p-states of Be-like C2+ ion which interact with the even-parity continua have been studied up to the C3+ 3d threshold limit. Using the variational R-matrix method, calculations have been performed in the initial 20 and final 22 state close-coupling approximations in the photon wavelength range 15–35 nm. The detailed photoionization processes of included multichannels are displayed in the partial photoionization cross sections, which contain a number of autoionizing Rydberg series of resonances converging to the C3+ 2p, 3s, 3p and 3d thresholds. In particular, the lower members of the Rydberg series showing irregular patterns of resonances, which lie above the C3+ 2p threshold, are identified and resonance positions Er, effective quantum numbers n*, and widths Γ are presented. Excellent agreement between length and velocity gauge results is found, along with overall good agreement with previous work, except for the discrepancies with the threshold behaviour of the OP (opacity project) result.