Abstract

An energy-based structural indicator for water, \(V_4\), has been recently introduced by our group. In turn, in this work we aim at: (1) demonstrating that \(V_4\) is indeed able to correctly classify water molecules between locally structured tetrahedral (T) and locally distorted (D) ones, circumventing the usual problem of certain previous indicators of overestimating the distorted state; (2) correlating \(V_4\) with dynamic propensity, a measure of the molecular mobility tendency, in order to seek for the existence of a connection between structure and dynamics within the supercooled regime. More specifically, in the first part of this work we will show that \(V_4\) accurately discriminates between merely thermally deformed local molecular arrangements and truly distorted molecules (defects). This fact will be made evident not only from radial distribution function results but also from the dynamic propensity distributions of the different kinds of molecules. In turn, we shall devote the second part of this work to finding correlations between T and D molecules with low- and high-dynamic-propensity molecules, respectively, thus revealing the existence of a link between local structure and dynamics, while also making evident the dominant role of the D molecules (defects) in the structural relaxation. Moreover, the availability of a proper molecular classification technique will enable us to study the timescale of such influence of structure on dynamics by defining a modified dynamic propensity measure and by applying it to the structured and unstructured water molecular states.

Graphic Abstract

中文翻译：

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基于能量的水分类指数的结构方面以及玻璃态松弛中的结构-动力学联系

摘要

我们小组最近引入了一种基于能量的水结构指标\（V_4 \）。反过来，在这项工作中，我们着眼于：（1）证明\（V_4 \）确实能够正确区分局部结构的四面体（T）和局部变形的（D）分子之间的水分子，从而规避了某些先前的常见问题。高估失真状态的指标；（2）将\（V_4 \）与动态倾向性进行关联，动态倾向性是分子迁移趋势的一种度量，目的是在过冷状态下寻找结构与动力学之间的联系。更具体地说，在本工作的第一部分中，我们将显示\（V_4 \）可以准确地区分仅热变形的局部分子排列和真正变形的分子（缺陷）。不仅从径向分布函数结果，而且从不同种类分子的动态倾向分布，这一事实将变得明显。反过来，我们将把这项工作的第二部分专门用于分别查找T和D分子与低动态倾向性分子和高动态倾向性分子之间的相关性，从而揭示局部结构与动力学之间存在联系，同时也要弄清楚D分子（缺陷）在结构松弛中的主导作用。而且，

图形摘要