Electronic structure of FeF₂and FeF₃studied by x-ray absorption and fluorescence spectroscopy

Abstract

High resolution investigations of polycrystalline FeF2 and FeF3 were performed by means of x-ray absorption and resonant x-ray fluorescence spectroscopy. The obtained F Kα fluorescence spectra of ionic FeF2 and FeF3 were analysed in comparison with the F Kα spectrum of the covalent anion TiF62- in solid K2TiF6. The FKα spectra of compounds under study consist of the main band accompanied by a low-energy shoulder. The latter can be associated with the valence subband of the Fe 3d – F 2p hybridized electron states. Strong high-energy shake-up satellites were observed in the F Kα spectra of these compounds when the excitation energy exceeds the F 1s ionisation threshold (∼690 eV). Information about local partial densities of states for FeF2 was obtained from a comparative analysis of Fe L and F K x-ray fluorescence and valence-band photoemission spectra.