Collective dynamics of liquid acetone investigated by inelastic X-ray scattering
Collective dynamics of liquid acetone investigated by inelastic X-ray scattering
复制标题
非弹性 X 射线散射研究液体丙酮的集体动力学
DOI：
10.1016/j.molliq.2021.115825
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发表时间：
2021
影响因子：
6
通讯作者：
Baron Alfred Q.R.
中科院分区：
文献类型：
--
作者：
Hosokawa Shinya;Kamiyama Takashi;Yoshida Koji;Yamaguchi Toshio;Tsutsui Satoshi;Baron Alfred Q.R.
使用安装在 SPring-8 BL35XU 上的高分辨率非弹性 X 射线散射 (IXS) 光谱仪在 1.9–41.2 nm−1 的宽 Q 范围内测量液体丙酮的动态结构因子 S(Q,ω)。观察到纵向声（LA）声子的高阻尼集体激发。使用广义 Langevin 形式并借助稀疏建模来分析 IXS 谱，以推导出拟合参数的合理 Q 依赖性。 LA声子激发的色散关系显示出与绝热声速约65%的高度正偏差，该偏差大于具有范德华相互作用的CCl4和苯等非极性液体中的色散关系，这可能是由于丙酮是极性液体。通过与现有的宏观动态特性进行比较，讨论了粘弹性松弛率和粘度等微观动态参数。快速和慢速粘弹性松弛分别对应于振动动力学和重定向相关性。
The dynamic structure factorsS(Q,ω) of liquid acetone were measured in a wideQrange 1.9–41.2 nm−1with a high-resolution inelastic X-ray scattering (IXS) spectrometer installed at BL35XU of the SPring-8. Highly damped collective excitations of the longitudinal acoustic (LA) phonons are observed. The IXS spectra were analyzed by using a generalized Langevin formalism with the help of a sparse modeling to deduce reasonableQdependences of the fitting parameters. The dispersion relation of the LA phonon excitations shows a highly positive deviation by about 65% from the adiabatic velocity of sound, which is larger than that in non-polar liquids such as CCl4and benzene with van der Waals interactions, due probably that the acetone is a polar liquid. Microscopic dynamic parameters, such as viscoelastic relaxation rates and viscosity, are discussed by comparing with existing macroscopic dynamic properties. The fast and slow viscoelastic relaxations correspond to the vibration dynamics and reorientation correlations, respectively.