Intensities and satellites of 4f-photoelectrons in thorium and uranium dioxides

In a comparison between photoelectron-spectroscopic intensities and theoretical orbital ionization cross-sections, it is found that whereas the intensities and cross-sections agree for the ratio of Th(4f) to O(1s) in ThO2, the ratio for U(4f) to O(1s) in UO2 differs from the theoretical ratio by 36%. It is shown that the deviation is attributable to the loss of U(4f) photoelectrons through the degradation of their kinetic energies into the tail on the high binding energy side of the spectrum. The results for ThO2 imply a linear dependence of the inelastic scattering mean free path on kinetic energy; the results for UO2 imply extensive configuration interaction between the 4f core-hole and unoccupied states of the cation, and they demonstrate the use of theoretical cross-sections to determine the extent. (author)