RAMAN AND FTIR SPECTRA OF RE(BrO3)3·9H2O(RE = Eu, Tb) AND ELECTRONIC TRANSITIONS IN Eu(BrO3)3·9H2O

Raman, FTIR spectra of Eu(BrO3)3·9H2O and Tb(BrO3)3·9H2O are recorded and analyzed. The observed bands are assigned on the basis of and H2O vibrations. Electronic transitions observed in the Raman spectra of Eu(BrO3)3· 9H2O are also investigated. In Tb(BrO3)3·9H2O the symmetry of anion is lowered from C3v to Cs due to distortion. The wavenumber value of the ν1 mode of anion is found to be decreased from that of free state and is due to hydrogen bonding in the crystal. The decrease in wavenumber values of stretching modes and the increase in wavenumber values of the bending modes of water molecules from free state values confirm that they form hydrogen bonds with oxygen atoms are bromate ions in agreement with the structural data. Further the spectral pattern of water molecules indicates the presence of hydrogen bonds of varying strengths. The electronic transitions observed in Eu(BrO3)3·9H2O suggest that Eu3+ ions are situated in the crystal at sites having symmetry higher than C2 or C1.