Oxidization/Reduction Process of Prussian Blue Film as Investigated by Valence-Differential Spectroscopy

摘要

The oxidization/reduction of a Prussian blue (Fe~(III)[Fe~(II)(CN)_6]_(3/4)4.2H_2O) film was investigated by valence-differential spectroscopy, which selectively extracts spectral components related to the oxidized/reduced metal. The spectroscopy results revealed weak absorption components hidden in a structureless spectrum above ～2.6 eV. We found a significant red shift of the charge-transfer (CT) transition of an electron from the 3d t_(2g) orbital of [Fe~(II)(CN)_6] to the 3d t_(2g) orbital of Fe~(III). We interpret the red shift in terms of the inhomogeneous broadening of the CT transition and selective oxidization/reduction.