Infrared Active Two?Phonon Processes in Cubic ZnS

Abstract

Results are presented of a study of the infrared transmission spectrum of cubic ZnS at room temperature. Besides the fundamental lattice absorption, a number of subsidiary bands due to the interaction of infrared radiation with more than one lattice phonon in the frequency range 250-800 cm - 1 have been observed. These multiphonon bands are explained using inelastic neutron scattering data for the four characteristic phonon frequencies at various critical points and applying selection rules.