VALENCY AND 4F COVALENCY OF CS2RBTBF7

Valency and 4f covalency of Cs2RbTbF7 were studied by x-ray-absorption near-edge-structure (XANES) spectroscopy at the Tb-LI-III, Tb-MIV,V, and F-K absorption thresholds as well as by 3d core-level photoemission (3d-PE). The availability of a chemically pure and stable sample allowed the observation of solely intrinsic spectral features in the core-level spectra, which characterize Cs2RbTbF7 as the tetravalent lanthanide compound with the weakest 4f-ligand hybridization known. Both the Tb final-state spectra, analyzed on the basis of a simplified Anderson single-impurity model, and the F-K XANES spectrum provide insight into 4fligand-p mixing in this compound. © 1995 The American Physical Society.