Electronic structure and x-ray-absorption spectra of wustite Fe1-xO

Electronic ground-state properties of Fe1-xO were calculated by the spin-unrestricted local-density self-consistent discrete variational method, with (2030)-atom clusters embedded in the crystal. Charge and spin distributions were determined for both ideal and defective compounds with the rocksalt structure. Effective atomic valence states and local magnetic moments were compared with interpretations of Mössbauer and neutron magnetic scattering data. Densities-of-states (DOSs) analyses were carried out and compared with FeO valence-band photoemission and optical spectra. K-edge x-ray-absorption near-edge spectra (XANES) for Fe sites were generated, using a multiple scattering approach. The variation of DOSs and XANES with local atomic arrangement was investigated to provide indications of measurable effects of lattice relaxation and metal valence shifts around defects.