Pronounced structural crossover in water at supercritical pressures.
Pronounced structural crossover in water at supercritical pressures.
复制标题
超临界压力水中明显的结构交叉。
DOI：
10.1088/1361-648x/ab94f1
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Cockrell C
中科院分区：
文献类型：
--
作者：
Cockrell C
人们对H2O在固态和低压液态下的许多相态以及它们之间的相变进行了大量的研究。使用分子动力学模拟，我们解决了迄今为止尚未探索的深超临界压力，没有质的转变被认为是发生，所有的属性预计将顺利变化。在这些模拟的基础上，我们预测，水在超临界压力下经历了一个结构跨越弗伦克尔线的压力高达45倍的临界压力。这为水相图提供了新的见解，并建立了超临界水的结构和动力学性质之间的联系。具体来说，交叉证明了一个尖锐的和明显的在低压下，在高压下，顺利，表示在对分布函数和本地协调的变化，符合动态过渡（所有振荡分子运动的损失）在Frenkel线上的相图。
There have been ample studies of the many phases of H 2 O in both its solid and low pressure liquid states, and the transitions between them. Using molecular dynamics simulations we address the hitherto unexplored deeply supercritical pressures, where no qualitative transitions are thought to take place and where all properties are expected to vary smoothly. On the basis of these simulations we predict that water at supercritical pressures undergoes a structural crossover across the Frenkel line at pressures as high as 45 times the critical pressure. This provides a new insight into the water phase diagram and establishes a link between the structural and dynamical properties of supercritical water. Specifically, the crossover is demonstrated by a sharp and pronounced at low pressures, and smooth at high pressures, signified by changes in the pair distribution functions and local coordination which coincide with the dynamical transition (the loss of all oscillatory molecular motion) at the Frenkel line on the phase diagram.