Electronic structure of FeF2 and FeF3 studied by x-ray absorption and fluorescence spectroscopy

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 K alpha. uorescence spectra of ionic FeF2 and FeF3 were analysed in comparison with the FK alpha spectrum of the covalent anion TiF62-in solid K2TiF6. The FK alpha 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 K alpha spectra of these compounds when the excitation energy exceeds the F 1s ionisation threshold (similar to 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. uorescence and valence-band photoemission spectra.