The electronic structures of Prussian blue analogue ACo[Fe(CN)6]H2O (A=Na, K) nano-size particles has been investigated by employing soft X-ray absorption spectroscopy (XAS) at the Fe and Co L edges. Both Fe and Co ions are found to be Fe2+-Fe3+ and Co2+-Co3+ mixed-valent, with the average valence of v(Fe)∼ 2.36 and v(Co)∼ 2.41. This finding suggests that the mechanism of the photo-induced spin transition in ACo[Fe(CN)6]H2O (A=Na, K) is not a simple spin-state transition of Fe2+-Co3+ → Fe3+-Co2+. The Fe ions in ACo[Fe(CN)6]H2O are also found to have a strong covalent bonding to (CN)- ligands, but a very weak bonding to O(H2O), while Co ions have a stronger bonding to O(H2O) than to (CN)- ligands.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation under Contract No. 2011-0022444 and in part by the 2013 Research Fund of the Catholic University of Korea. N. V. M. acknowledges support by the National Foundation for Science and Technology Development (NAFOSTED) of Vietnam and Research Foundation-Flanders (FWO) of Belgium (Code FWO 2011.23). Synchrotron experiment was performed at the HSRC under the approval of the Proposal Assessing Committee.
- Electronic structure
- Molecular magnets
- Prussian blue