Double ionization of atomic cadmium

We have recorded the double photoionization spectrum of atomic Cd at four different photon energies in the range 40-200 eV. The main channel is single ionization and subsequent decay of excited Cd+ states, some involving Coster-Kronig processes, whereas direct double ionization is found to be weak. The decay of the excited Cd+ states shows a strong selectivity, related to the configuration of the final state. Double ionization leading to the Cd2+ ground state is investigated in some detail and is found to proceed mainly through ionization and decay of 4d correlation satellites. The most prominent autoionization peaks have been identified with the aid of quantum-mechanical calculations.