Central Peak of KH3 (SeO3)2 Studied by Light Scattering

Abstract

The central peak in the light scattering spectrum of K${\mathrm{H}}_3$ ${\left(\mathrm{S}\mathrm{e}{\mathrm{O}}_3\right)}_2$ has been found to depend on the history of a specimen: The central component of an as-grown crystal shows remarkable increase in intensity near the phase-transition temperature $T_{\mathrm{tr}}$, while after repeated measurements in the temperature range between - 30°C and $T_{\mathrm{tr}}$, the central component becomes very weak even near $T_{\mathrm{tr}}$. The origin of the central peaks observed in the as-grown K${\mathrm{H}}_3$ ${\left(\mathrm{S}\mathrm{e}{\mathrm{O}}_3\right)}_2$ crystals seems to be an extrinsic one.