Far-Infrared Absorption in Cubic ZnS

Abstract

<p>The shapes, frequencies and intensities of far-infrared absorptions in cubic ZnS, measured by a high-resolution, low-noise far-infrared Fourier transform spectrometer system, and attributable to two-phonon processes, were found to compare favourably with a theoretical two-phonon density of states curve calculated with a program supplied by G. Dolling (1974). The parameters used in the theory were derived from inelastic neutron scattering experiments by Vagelatos et. al. (1974). Two-phonon combinations and their locations in the Brillouin zone which give rise to strong features in the two-phonon density of states were identified by comparing theory and experiment. Important critical points were discovered on or near the zone boundary and not only at the symmetry points P, X, L and W as previously suggested.</p>