Electronic Absorption Spectrum of LiMnO4·3H2O in LiClO4·3H2O

Polarized absorption spectra of single crystals of LiClO4·3H2O/LiMnO4·3H2O have been measured at 4.2°K. The 5200-Å band of MnO4− has been identified as a T12←A11 transition; the 3600-Å band has been identified as T11←A11 or, just possibly, E1←A11; and the 3000-Å band has been identified as T12←A11. A brief discussion of two higher energy transitions is also provided. The site splitting of the 1A1 and 1E states, which are produced from the T2 state upon reduction of symmetry from Td to C3v, is large ( ∼500 cm−1). Vibronic activity is observed in the 5200 - Å1T2←1A1 transition and is discussed.