We report the first observation of the near-infrared luminescence in RbI crystals doped with the MnO 42- (manganate) and MnO 4- (permanganate) ions. NIR luminescence spectra of the MnO 4- and MnO 42- ions show similarity in both the spectral region (8500-11 000cm -1 ) and the appearance of well-resolved vibronic structure at 4K caused by the electron coupling with the bending (e) modes of the impurity ions. This fine structure is considered as a result of e e and t 2 e Jahn-Teller effect in the ground and excited electronic states, respectively. MnO 42- NIR luminescence is attributed to the d-d ( 2 T 2 -> 2 E) transition of a single d-electron of Mn 6+ .. The origin of the luminescence in case of MnO 4- -doped iodides is connected with the transient Mn 6+ state, which is generated by the illumination-induced charge transfer process. The possibility of thermal population of Mn d-orbitals in case of MnO 4- ion is also discussed.
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