Cyanate Ion in Alkali Halides: New Vibrational Levels and Interpretation of Localized Lattice Modes

Abstract

The infrared absorption of alkali halide single crystals containing NCO⁻ impurity at concentrations up to about 1 mole % has yielded new information about the internal vibrational levels of the cyanate ion. Satellite lines near ν₃ and its combinations have been shown to arise from neighbor pairs of cyanate ions in the host lattice. Absorptions of the type ν₃±ν_k, where ν_k is of the order of 80 to 180 cm⁻¹ and is strongly dependent upon the host lattice, have been observed; and the relation of ν_k to the impurity‐induced localized lattice modes is discussed.