HYBRIDIZATION, CRYSTAL-FIELD AND MAGNETISM IN RARE-EARTHS AND CORE LEVEL SPECTROSCOPY

The usefulness and capability of core level spectroscopies for probing the 4f states of rare earth systems are discussed theoretically on the basis of atomic multiplet calculations including various ''solid state effects''. By choosing some Ce compounds, the hybridization strength between the Ce 4f orbital and ligand orbitals are shown to be well reflected in 3d and 4d core X-ray photoemission spectra. The light polarization dependence of 3d and 4d core X-ray absorption, such as linear dichroism and magnetic circular dichroism, is shown to be a powerful characteristic which can be used to detect the distribution and symmetry of 4f electron occupation.