Dynamics of Highly Condensed Molecular Solids by Laser-Induced Acoustic Phonon Spectroscopy

高压声波布里渊光谱已经应用于分子固体硫化氢（H2S）和二氧化碳（CO2）在压力高达6 GPa和室温下。将布里渊声速的角依赖关系的实验值与任意方向弹性波的Every表达式的计算结果进行最佳拟合，得到了在金刚石-砧砧高压电池中生长的H2S和CO2三相晶体的取向。声速作为压力的函数，可以在任何方向、折射率、密度和弹性常数上进行原位测定。该方法为系统研究超高压下冷凝气体的弹性特性和相变提供了一种手段。

High-pressure acoustic Brillouin spectroscopy has been applied to molecular solids hydrogen sulfide (H2S) and carbon dioxide (CO2) at pressures up to 6 GPa and room temperature. The best fit of the angular dependence of Brillouin acoustic velocities between experimental values and calculations based on Every's expression for elastic waves of an arbitrary direction yielded the orientation of H2S and CO2 cubic-phase crystal grown in the diamond-anvil high-pressure cell. In situ determinations of sound velocities, as a function of pressure, could be made for any direction, the refractive index, the density, and the elastic constants.This method provides a mean for the systematic study of elastic properties and phase transitions of condensed gases under ultrahigh pressures.