An odd-parity localised model for the valence mixing of samarium compounds

Abstract

A variational ground state of samarium monochalcogenides is investigated using a one-dimensional periodic Anderson Hamiltonian. The f orbital on one site is taken to be admixed with d orbitals on neighbouring sites rather than on the same site. This odd-parity form corresponds to a localised limit of Steven's model (1978). A complication associated with the use of non-orthogonal orbitals is dealt with by using a generating-function method. Pressure-volume relations that can reproduce experimental phase changes are obtained by taking into account lattice elastic energies.