On limits of compact inner shell approximation applicability to rare-earth metals

The paper studies limits of rare-earth metal applicability of a compact inner shell approximation in the pseudopotential theory (approximation of strongly localized inner shells of ionic cores). For 15 rare-earth metals the 5s, 5p, 4d and 4f outer atomic orbitals were investigated using the quantitative criterion, showing in which cases the distinction of outer electron wave functions psisub(t)sup(cr) in a crystal from corresponding psisub(t)sup(i) of an isolated ion is necessary to be taken into account. It is shown that for all investigated rare-earth metals, psisub(5p)sup(cr) cannot be related to bound core states for which the compact shell approximation is valid. A general structure is established for model pseudopotentials of rare-earth metals