Continuous and Discontinuous Dynamic Crossover in Supercooled Water in Computer Simulations

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• 作者：Zhonghua Ma ; Jicun Li ; Feng Wang
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2015
• 出版时间：August 20, 2015
• 年：2015
• 卷：6
• 期：16
• 页码：3170-3174
• 全文大小：300K
• ISSN：1948-7185

文摘

The dynamic crossover behavior of supercooled water as described by the first-principle based WAIL potential was investigated. Below the second liquid鈥搇iquid critical point, the viscosity shows a discontinuous jump consistent with a first-order phase transition between the high density liquid and the low density liquid. Above the critical point, a continuous transition occurs with only the first derivative of viscosity being discontinuous, and the dynamic crossover temperature is about 8 K below the thermodynamic switchover temperature. The 8 K shift can be explained by a delay in dynamic crossover, which does not occur until the more viscous liquid starts to dominate the population and jams the flow. On the basis of finite-size effects observed in our simulations, we believe that dynamic discontinuity may be observable above the critical point in confined water when the confinement is on a length scale shorter than the spatial correlation.