Temperature Dependence of the Raman, Brillouin and Rayleigh Scattering by Crystalline Quartz

Abstract

Crystalline quartz undergoes a phase transition at 573°C from its low temperature (α) phase with point symmetry D₃ to its high temperature (β) phase with point symmetry D₆. At the transition temperature there are anomalous changes in many of its properties [1]. In 1956, Yakovlev et al. [2] reported that as quartz underwent its transition it exhibited opalescence very similar to the critical opalescence observed in a liquid-vapor transition. Almost concurrently, Ginzburg[3] applied Landau’s theory of second order phase transitions to quartz and was able to calculate the increase in the intensity of light scattered at the transition temperature, which was in agreement with Yakovlev’s experiment. Ginzburg also predicted that the order parameter used to describe the quartz transition would be connected with one branch of the optic vibrations. The frequency of this mode should go to zero as the transition temperature is approached, while the fluctuations of the order parameter become very large; thus the intensity of the scattered light should increase. Early experiments [4] indicated that the mode exhibiting this behavior was the Raman active vibration with a frequency of 207 cm⁻¹ at room temperature.