Covalency in the electronic structure of Fe₃O₄: An ultraviolet inverse photoemission investigation

The unoccupied electronic structure of an open d-shell transition metal oxide, namely Fe3O4, has been addressed by measuring ultraviolet angle-integrated inverse photoemission (IP) spectra acquired in the isochromat mode (hv=10.2-24 eV). Exploitation of photon energy dependence of symmetry-projected IP cross-sections and comparison with the O 1 s X-ray absorption spectrum allow us to recognize a strong covalent admixture of Fe [3 d; 4 (sp)]-and O (2 p)-derived states in this compound. © 1991 Springer-Verlag.