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Continuous and Discontinuous Dynamic Crossover in Supercooled Water in Computer Simulations.
Zhonghua Ma1, Jicun Li1, Feng Wang1
1Department of Chemistry and Biochemistry, University of Arkansas , 119 Chemistry Building, Fayetteville, Arkansas 72701, United States.
The Journal of Physical Chemistry Letters
|August 2, 2016
Summary
Supercooled water exhibits distinct dynamic crossover behaviors. Below the critical point, viscosity changes abruptly, while above it, the transition is continuous with a notable delay in dynamic crossover.
Area of Science:
- Physical Chemistry
- Computational Fluid Dynamics
- Materials Science
Background:
- Supercooled water exhibits complex phase behavior, including a hypothesized second liquid-liquid critical point.
- Understanding water's dynamic properties under varying conditions is crucial for numerous scientific and industrial applications.
Purpose of the Study:
- To investigate the dynamic crossover behavior of supercooled water using the first-principle based WAIL potential.
- To analyze the nature of viscosity transitions above and below the second liquid-liquid critical point.
Main Methods:
- Utilizing the first-principle based WAIL potential for molecular simulations.
- Analyzing viscosity changes and dynamic crossover phenomena in supercooled water.
Main Results:
- Below the critical point, viscosity shows a discontinuous jump, indicative of a first-order phase transition between high-density liquid (HDL) and low-density liquid (LDL).
- Above the critical point, a continuous transition is observed, with the dynamic crossover temperature approximately 8 K below the thermodynamic switchover temperature.
- The 8 K shift is attributed to a delay in dynamic crossover, occurring when the more viscous liquid dominates and impedes flow.
Conclusions:
- Dynamic discontinuity in supercooled water may be observable above the critical point in confined systems.
- Confinement on a length scale shorter than spatial correlation is key for observing dynamic discontinuity above the critical point.
Keywords:
dynamic discontinuityfragile to strong crossoverglass dynamicsliquid−liquid transitionviscosityMore Related Videos
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