From Single-Particle to Collective Dynamics in Supercooled Liquids
From Single-Particle to Collective Dynamics in Supercooled Liquids
复制标题
过冷液体中从单粒子到集体动力学
DOI：
10.1021/acs.jpclett.3c00959
复制
发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Richert, Ranko
中科院分区：
文献类型：
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作者：
Matyushov, Dmitry V.;Richert, Ranko
近年来人们认识到光子相关（PCS）和介电（BDS）磁化谱之间的巨大差异是由于它们各自与单粒子和集体动力学的关联。这项工作提出了一个模型，该模型捕获了集体动力学（BDS）的较窄宽度和移位的峰值位置，给出了从PCS研究中得出的单粒子磁化率。连接集体动力学和单粒子动力学的谱只需要一个可调参数。这个常数解释了分子角速度与一级和二级单粒子弛豫时间之比之间的相互关系。该模型对三种过冷液体，甘油，丙二醇和磷酸三丁酯进行了测试，并证明了BDS和PCS光谱之间的差异。由于PCS光谱在一系列过冷液体中似乎是相当普遍的，因此该模型为使更具体的材料介电损耗谱合理化提供了第一步。
It has been recognized recently that the considerable difference between photon correlation (PCS) and dielectric (BDS) susceptibility spectra arises from their respective association with single-particle and collective dynamics. This work presents a model that captures the narrower width and shifted peak position of collective dynamics (BDS), given the single-particle susceptibility derived from PCS studies. Only one adjustable parameter is required to connect the spectra of collective and single-particle dynamics. This constant accounts for cross-correlations between molecular angular velocities and the ratio of the first- and second-rank single-particle relaxation times. The model is tested for three supercooled liquids, glycerol, propylene glycol, and tributyl phosphate, and is shown to provide a good account of the difference between BDS and PCS spectra. Because PCS spectra appear to be rather universal across a range of supercooled liquids, this model provides a first step toward rationalizing the more material-specific dielectric loss profiles.