RAMAN SCATTERING STUDY OF INTERACTIONS OF CYANIDE IMPURITIES IN POTASSIUM-CHLORIDE UNDER VARIATION OF TEMPERATURE AND CONCENTRATION (NEAR-NEIGHBOR PAIRING, DAVYDOV SPLITTING, MOTIONAL NARROWING)

The interactions of CN('-) impurities in KCl have been investigated by Raman light scattering in the spectral region of the CN('-) stretching frequency. The low temperature width and observed motional narrowing of the primary peak assigned to isolated cyanide impurities is attributed to interaction with non-near-neighbor defects in the lattice. A splitting has been observed in a spectral feature attributed to CN('-) pairs and attributed to a dynamical interaction (Davydov splitting). This suggests a model for nearest-neighbor pairing. The relative positions and intensities of downshifted sidebands are explained by this model.