Infrared and Raman spectra of alkali halide/NO−3 systems

Detalled Raman spectra of the NO−3 ion substitutionally isolated in Rbl, Kl and KCl have been investigated at various temperatures between 77 and 300 K. These spectra, together with their corresponding infrared spectra, have been used to study the effective symmetry of these systems. Changes in the infrared and Raman activities of some of the modes of the NO−3 ions have been observed as the samples were cooled. Two different symmetries, one at room and the other at low temperature, have been identified as D3 and C3v respectively.