X-ray absorption studies of CeO2, PrO2, and TbO2. I. Manifestation of localized and extended f states in the 3d absorption spectra

The 3d x-ray absorption spectra of CeO2, PrO2, and TbO2 show some interesting features. The main lines in these spectra are unusually broad. They are identified by comparison with the 3d-4f atomiclike multiplets observed in Z-1 elements. In these oxides, the positions and the similar form of a weaker structure which is systematically observed at about 3--5 eV above each main line indicate that it is due to the transitions to the extended f type of states. These observations demonstrate a specific behavior of the outermost f electron which differentiates these oxides from other intermediate-valence materials and from the Ce intermetallic compounds