Abstract
X-ray absorption spectroscopy (XAS) at the 3d and 2p thresholds as well as 3d core-level photoemission (XPS) were used to investigate the electronic structure of and . From non- atomic 4f-related spectral features in the 3d XAS spectra, 4f-ligand hybridization is clearly visible in the case of and—less pronounced—in . For the latter compound, -edge XAS data support the view of a finite 4f admixture to the Tb-F bonding orbitals, while the -edge spectrum reflects more explicitly tetravalency. From 3d XPS measurements, an estimate of ≃12 eV is obtained for the core-hole–4f Coulomb interaction in . The high-energy spectra characterize both fluorine compounds as tetravalent insulators with covalent bonding and clearly show a decrease in 4f-ligand mixing, i.e., an increase in 4f localization, with respect to the corresponding dioxides.
- Received 5 October 1987
DOI:https://doi.org/10.1103/PhysRevB.37.1376
©1988 American Physical Society