Yoon Tae Jun, Ha Min Young, Lazar Emanuel A, Lee Won Bo, Lee Youn-Woo
School of Chemical and Biological Engineering, Institute of Chemical Processes , Seoul National University , Seoul 08826 , Republic of Korea.
Materials Science and Engineering , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States.
J Phys Chem Lett. 2018 Nov 15;9(22):6524-6528. doi: 10.1021/acs.jpclett.8b02715. Epub 2018 Nov 2.
The dynamics of supercritical fluids, a state of matter beyond the gas-liquid critical point, changes from diffusive to oscillatory motions at high pressure. This transition is believed to occur across a locus of thermodynamic states called the Frenkel line. The Frenkel line has been extensively investigated from the viewpoint of the dynamics, but its structural meaning is still not well-understood. This Letter interprets the mesoscopic picture of the Frenkel line entirely based on a topological and geometrical framework. This discovery makes it possible to understand the mechanism of rigid-nonrigid transition based not on the dynamics of individual atoms but on their instantaneous configurations. The topological classification method reveals that the percolation of solid-like structures occurs above the rigid-nonrigid crossover densities.
超临界流体是一种处于气-液临界点之上的物质状态，其动力学在高压下从扩散运动转变为振荡运动。这种转变被认为发生在一条称为弗伦克尔线的热力学状态轨迹上。从动力学角度对弗伦克尔线进行了广泛研究，但其结构意义仍未得到很好的理解。本文完全基于拓扑和几何框架解释了弗伦克尔线的介观图像。这一发现使得有可能基于原子的瞬时构型而非单个原子的动力学来理解刚性-非刚性转变的机制。拓扑分类方法表明，在刚性-非刚性交叉密度之上会发生类固体结构的渗流。
