Double photoionization of copper involving the 3d and 3p subshells

Abstract

The excitation of the M shell of atomic copper in the 40–125 eV photon energy range with synchrotron radiation (at LURE in Orsay) followed by the detection of Cu+ and Cu2+ ions has allowed us to point out a preferential decay of the Rydberg states 3p53d104snl (1=0 and 2) into double ionization channels (3d9 and 3d84s final ionic states) in contrast to the relaxation of the core excited states 3p53d104s2(2P3/2 and 2P1/2) into single ionization routes (satellite 3d84s2e1 channels, with 1=1 and 3). The present study also shows that the contribution of the direct double photoionization involving the 3d subshell is continuously increasing from the double ionization thresholds and reaching about half the single 3d photoionization cross section in the 100–120 eV energy range, i.e. above the 3p single ionization thresholds.