Raman study of the charge transferred metastable state leading to the photoinduced magnetic phase transition in rubidium manganese hexacyanoferrate

The photoinduced charge transfer process in Rb0.94Mn[Fe(CN)6]0.98⋅0.2H2O was investigated by observing the pair valence states of adjacent metal ions by Raman spectroscopy near the high-temperature end of the hysteresis loop. After prolonged irradiation at the ligand-to-metal charge transfer band, the FeIII–CN–MnII pair valence state corresponding to the high-temperature phase was completely depleted, and the FeII–CN–MnIII pair corresponding to the low-temperature phase appeared. In addition, peaks ascribable to FeII–CN–MnII and FeIII–CN–MnIII pair valence states were found.