Photoionization studies of the 2p resonances of atomic calcium

The Ca 2p resonances at 345–355 eV were studied by photoion and photoelectron spectroscopy using monochromatized synchrotron radiation and atomic-beam technique. The analysis of the excitation and decay of these resonances shows strong configuration mixing between the different subshells of the valence electrons 4s, 3d, and 4p. In the case of the 2p_3/2^-1 resonance structure at 348 eV there are two excited states with nearly equal contributions from the configuration 2p⁵3d4s² and 2p⁵3d²4s, which gives rise to strong variations of the resonantly enhanced 3p⁴(3d,4s)³ photoelectron lines when scanning the photon energy across the resonance.