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

高压声学布里渊光谱已被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。布里渊声速的角度依赖性的最佳拟合的实验值和计算的基础上的任意方向的弹性波的Every的表达式产生的金刚石砧高压细胞中生长的H2S和CO2 α-相晶体的取向。该方法可以在现场测量任意方向的声速、折射率、密度和弹性常数，为系统研究超压下凝聚态气体的弹性性质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.