Continuous and Discontinuous Dynamic Crossover in Supercooled Water in Computer Simulations

by Ma, Zhonghua; Li, Jicun; Wang, Feng

The dynamic crossover behavior of supercooled water as described by the first-principle based WAIL potential was investigated. Below the second liquid liquid 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.

Journal
Journal of Physical Chemistry Letters
Volume
6
Issue
16
Year
2015
Start Page
3170
ISBN/ISSN
1089-5639; 1948-7185
PMID
27476514
DOI
10.1021/acs.jpclett.5b01348