Electronic and vibrational spectra of MnO 2−4 in KBr crystals

Abstract

Two new features have been observed in the electronic spectrum of KBr crystals doped heavily with MnO 2− 4 ions. The band at 870 nm is assigned to the crystal field transition e → t 2. The band at 600 nm shows a series of vibrational sub-bands at an interval of 740cm −1 and is ascribed to the coupling between electronic transition and totally symmetric mode of the ion. A line at 830cm −1, ascribed to totally symmetric mode v 1( A 1), has been observed for the first time in the Raman spectrum. I.R. spectrum of KBr: MnO 2− 4 shows four lines—one due to MnO 2− 4 in Td symmetry and the other three to the split components of v 3( T 2) for MnO 2− 4 in Cs symmetry. I.R. spectrum of KBr: MnO 2− 4: Ca 2+ shows another s of four lines—one due to MnO 2− 4 in Td symmetry and the other three to the v 3( T 2) mode of the ion in C 2 v symmetry. The v 1( A 1) line could not be observed in the i.r. spectra.