RELIABILITY OF CONVENTIONAL CRYSTAL-FIELD MODELS IN F-ELECTRON SYSTEMS

Crystal field models commonly applied to explain the electronic proper ties of solid f-electron compounds are discussed from the point of vie w of their inherent limitations and the false conclusions they may lea d to. Both phenomenological and ah initio approximate models are consi dered. The discussion is based on generalized perturbation model calcu lations of the crystal field parameters for europium, uranium, plutoni um and neptunium ions in various crystals. The results reveal the inad equacy of various electrostatic approaches and the correctness of mode ls based on renormalization terms.