Phase transition of DSP and DDSP

Abstract

A brief review is represented for the study on the phase transition mechanism of Ca₂Sr(C₂H₅CO₂)₆ (DSP) and its deuterated compound DDSP. Effect of the deuteration of all hydrogen sites of the propionate molecule is expected to change only the molecular moment of inertia in the structural basement of the crystal. The X-ray diffraction study of DDSP confirms that the geometrical structure of the propionate molecule also does not show any change due to deuteration compared with DSP. Dielectric, optical and light scattering measurements of DDSP reveal a dynamical property of the phase transition. The results of these experiments elucidate finally a minor role of the order-disorder motion of the propionate molecule in the phase transition mechanism as a “trigger.”