NEAR-THRESHOLD DOUBLE PHOTOIONIZATION IN ZN AND HG

Valence photoelectron spectra of Zn and Hg have been recorded by using monochromatized synchrotron radiation in ultraviolet region and monoc hromatized Al Kalpha radiation (hnu = 1487 eV), respectively. In the r egion of the double-ionization thresholds, satellite states associated with the nd-1 single-hole states (n = 3 for Zn and n = 5 for Hg) are observed above the nd10 1S double-ionization threshold. The Auger deca y of these satellites may account significantly in the formation of th e 1S state of the dication. In case of Zn, the asymmetric profile of t he main satellite lying above the 3d10 1S double-ionization threshold suggests the existence of a coupling between the discrete satellite st ate with this underlying shake-off continua.