Detailed Fe 3d electronic structures of Prussian blue analogs studied by X-ray absorption spectroscopy

Abstract

Herein, we studied the detailed electronic structures of Prussian blue analogs with hexacyanoferrate around Fe L- and K absorption edges using room temperature X-ray absorption spectroscopy (XAS). Fe is trivalent for all the synthesized samples. By L3-edge XAS measurements, the excitation from Fe 2p3/2 core level to the 3d (t2g↓), 3d (eg↓), 3d (eg↑) states, and the π*, and σ* states of the Fe–CN molecular orbitals are identified with 3d (t2g↑)3 3d (t2g↓)2 configuration. The same excitation from the 1 s core level is identified using Fe K-edge XAS spectra. The relationship between lattice constants and the energy difference between 3d (t2g↓) to π* and σ* transitions from the Fe 2p3/2 core level suggests that the change in the lattice constant influences the electronic structure near the Fe atom.