Heating-and pressure-induced transformations in amorphous and hexagonal ice: A computer simulation study using the TIP4P/2005 model
Heating-and pressure-induced transformations in amorphous and hexagonal ice: A computer simulation study using the TIP4P/2005 model
复制标题
DOI：
10.1063/1.4998747
复制
发表时间：
2017-08-21
影响因子：
4.4
通讯作者：
Giovambattista, Nicolas
中科院分区：
文献类型：
--
作者：
Engstler, Justin;Giovambattista, Nicolas
我们通过使用TIP 4P/2005水模型进行广泛的非平衡分子动力学模拟来表征玻璃态水的相行为。具体而言，我们研究了（i）低密度（LDA）和高密度非晶冰（HDA）之间的压力诱导转变，（ii）六方冰（I-h）的压力诱导非晶化（PIA），（iii）高压下加热诱导LDA到HDA的转变，（iv）低压和负压下加热诱导HDA-to-LDA的转变，（v）LDA和HDA的玻璃化转变温度作为压力的函数，和（vi）LDA在等压加热和等温减压（在负压下）时的稳定性极限。系统地研究了这些转变，在很宽的温度和压力范围内，使我们能够构建玻璃态TIP 4P/2005水的P-T相图。我们的结果是在定性与实验观察和P-T相图得到的玻璃态ST 2水，表现出液-液相变和临界点。我们还讨论了冰I-H的PIA机制，表明这是一个两步过程，首先，氢键网络（HBN）被扭曲，然后HBN突然崩溃。值得注意的是，崩溃的HB在冰I-H时发生的平均分子取向顺序，衡量四面体的HBN，是相同的顺序，在LDA，这表明一个共同的机制LDA-HDA和I-H-HDA转换。出版社：AIP Publishing
We characterize the phase behavior of glassy water by performing extensive out-of-equilibrium molecular dynamics simulations using the TIP4P/2005 water model. Specifically, we study (i) the pressure-induced transformations between low-density (LDA) and high-density amorphous ice (HDA), (ii) the pressure-induced amorphization (PIA) of hexagonal ice (I-h), (iii) the heating-induced LDA-to-HDA transformation at high pressures, (iv) the heating-inducedHDA-to-LDA transformation at low and negative pressures, (v) the glass transition temperatures of LDA and HDA as a function of pressure, and (vi) the limit of stability of LDA upon isobaric heating and isothermal decompression (at negative pressures). These transformations are studied systematically, over a wide range of temperatures and pressures, allowing us to construct a P-T phase diagram for glassy TIP4P/2005 water. Our results are in qualitative agreement with experimental observations and with the P-T phase diagram obtained for glassy ST2 water that exhibits a liquid-liquid phase transition and critical point. We also discuss the mechanism for PIA of ice I-h and show that this is a two-step process where first, the hydrogen-bond network (HBN) is distorted and then the HBN abruptly collapses. Remarkably, the collapse of the HB in ice I-h occurs when the average molecular orientations order, a measure of the tetrahedrality of the HBN, is of the same order as in LDA, suggesting a common mechanism for the LDA-to-HDA and I-h-to-HDA transformations. Published by AIP Publishing.