K-shell photoionization of Be-like carbon ions: experiment and theory for C2+

Absolute cross-section measurements for K-shell photoionization of Be-like C 2+ ions have been performed in the photon energy range 292–325 eV. These measurements have been made using the photon–ion merged-beam endstation at the Advanced Light Source, Lawrence Berkeley National Laboratory. Absolute measurements compared with theoretical results from the R -matrix method indicate that the primary C 2+ ion beam consisted of 62% ground-state (1s 2 2s 2 1 S) and 38% metastable state (1s 2 2s2p 3 P o ) ions. Reasonable agreement is seen between theory and experiment for absolute photoionization cross sections, resonance energies and autoionization linewidths of K-shell-vacancy Auger states.