Valence electronic state density in thorium dioxide

Abstract

This work analyses the fine low energy (0-40 eV) X-ray photoelectron spectra of ThO2, taking into account relativistic X?-discrete variation electronic structure calculations for the ThO8 (D4h) cluster reflecting thorium's close environment in ThO2. As a result, it was theoretically shown and experimentally confirmed that Th5f electrons in ThO2 can participate directly (~0.6 Th5f electrons) in chemical bond formation.Th6p electrons were shown to be a significant part (~0.44 Th6p electrons) not only of inner valence molecular orbitals, but to play a significant role in outer valence molecular orbitals formation, as well. Inner valence molecular orbitals composition and sequent order were established to belong to the binding energy range of 13 eV to 40 eV. The valence electronic state density in the range of 0-40 eV in ThO2 was also calculated. For the first time, these data allowed an interpretation of the fine X-ray photoelectron spectra (0-40 eV) and high resolution O4,5(Th) X-ray emition spectral structure (~60 - ~85 eV) of ThO2.