EVALUATION OF RAMAN-SPECTRA OF SOLUTIONS WITH PREDOMINANTLY IONIC METAL-OXYGEN INTERACTIONS

The assignment of infrared and Raman bands in the low-wavenumber (0-500 cm-1) region of molten salts and glasses is complicated by the difference in the selection rules for infrared and Raman activity. Assignments are presented for several molten and glassy nitrates for infrared-active (antisymmetric metal-oxygen motions) and Raman-active (symmetrical metal-oxygen motions) vibration modes. Bands associated with monomolecular reorientational motion of the polarizability anisotropy (Raman) and dipole moment (infrared) may also contribute intensity in the 0-200 cm-1 region. A Raman band at about 500 cm-1 which was detected previously in solutions of lithium nitrate in molten (K, Na)NO3 has been reassigned to the glass of the container wall.