Many-electron effects in th $5p$ and $5s$ X-ray photoelectron spectra of ThO$_2$

The Th $5p$ photoelectron spectrum of the ThO$_2$ oxide exhibits an anomalous spin–orbit splitting, intense satellite, and a poorly observable very strongly broadened Th $5s$ line. The Th $5p$ and Th $5s$ photoelectron spectra are calculated in this work using the configuration interaction and spectral (Green's) function methods in the basis of atomic Hartree–Fock functions. The results are in good agreement with experiment and indicate that the structure of these spectra is determined by interactions of the photoionization-induced $5p^{-1}$ and $5s^{-1}$ states with the $5d^{-2}5f(\varepsilon f)$ and $5p^{-1}5d^{-1}(\varepsilon f)$ satellite states including two holes and one electron in the discrete or continuous spectrum.