Manifestation of doubly excited atomic states in the photoionization cross-sections of Ar, Kr and Xe in the vicinity of the subvalence ns-shell threshold

Energy dependences of the total and partial ns-photoionization cross-sectio ns in the vicinity of the ns-subvalence shell threshold were measured for t he rare-gas atoms using photon-induced fluorescence spectroscopy. A resolut ion of 4.5, 3, and 1 meV was attained for Ar, Kr and Xe, respectively. The experimental cross-sections exhibit many well-resolved resonances of differ ent shapes which are connected with the photoionization through the doubly excited atomic states. Calculated photoionization cross-sections of Ar and Kr show that some resonances are determined by doubly excited states includ ing strongly delocalized n'f-excited electrons. (C) 2001 Elsevier Science B .V. All rights reserved.