Decay of the Xe 4d to np excitations: resonant shake-off versus shake-up and spectator transitions

Resonant photoelectron spectra were measured in the photon energy range of Xe 4d to np excitations to study multielectron processes associated with the decay of these resonances. The results show a large fraction of shake-off electrons in the total decay rate and indicate an increase of this fraction with increasing principal quantum number n of the photoexcited electron. Higher resolution measurements reveal that this increase accompanies a decrease in the corresponding probability for shake-up transitions. The consequences of this behaviour regarding double excitations and double Auger decay above the 4d ionisation threshold are discussed.