Raman scattering from crystalline NaNO3 has been observed in all polarization orientations. Except for small intensity contributions in some orientations which are probably due to depolarization effects in the birefringent crystal, the polarizability activities of both internal and external modes follow the expected symmetry selection rules. From relative intensity considerations, the bands at 185 and 98 cm-1 have been designated as the Raman-active librational and translational lattice modes, respectively. This assignment has been confirmed by the comparison of the lattice spectra of Na14NO3 and Na15NO 3 at 35°K, where an isotope shift is observed only on the lower frequency band. No evidence of mixing between these Eg lattice modes has been observed.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry