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Theory of core-level x-ray spectroscopy for Fe based mixed-valence systems
Munetaka Taguchi
Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), Ikoma, Nara, Japan
We will show our results of Magnetite and Myoglobin which are a typical
example of the mixed valence systems. We have examined the electronic
structure of Magnetite by hard x-ray photoemission spectroscopy (HAXPES)
and that of Myoglobin by resonant x-ray inelastic scattering (RIXS). In
Magnetite, Fe 2p HAXPES spectrum shows the strong enhancement of the
lower binding energy peak, which is conventionally assigned to the Fe2+
ions. Observed spectra were compared with the extended full-multiplet
model including the well-screening channel. For Myoglobin, the
experimental RIXS spectra exhibit complex spectral feature that spread
up to 10 eV. Calculations indicate a finite positive/negative
charge-transfer energy between the heme-Fe 3d and ligand states for
Fe2+/Fe3+. Thus, the energy difference between the ligand and Fe 3d
states determines the charge properties of Myoglobin.