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

Abstract

Raman, FTIR spectra of Eu ( BrO 3)3·9 H 2 O and Tb ( BrO 3)3·9 H 2 O are recorded and analyzed. The observed bands are assigned on the basis of [Formula: see text] and H 2 O vibrations. Electronic transitions observed in the Raman spectra of Eu ( BrO 3)3· 9 H 2 O are also investigated. In Tb ( BrO 3)3·9 H 2 O the symmetry of [Formula: see text] anion is lowered from C 3 v to C s due to distortion. The wavenumber value of the ν1 mode of [Formula: see text] 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 ( BrO 3)3·9 H 2 O suggest that Eu 3+ ions are situated in the crystal at sites having symmetry higher than C 2 or C 1.