Time scales of supercooled water and implications for reversible polyamorphism

Abstract

Deeply supercooled water exhibits complex dynamics with large density fluctuations, ice coarsening and characteristic time scales extending from picoseconds to milliseconds. Here, we discuss implications of these time scales as they pertain to two-phase coexistence and to molecular simulations of supercooled water. Specifically, we argue that it is possible to discount liquid–liquid criticality because the time scales imply that correlation lengths for such behaviour would be bounded by no more than a few nanometres. Similarly, it is possible to discount two-liquid coexistence because the time scales imply a bounded interfacial free energy that cannot grow in proportion to a macroscopic surface area. From time scales alone, therefore, we see that coexisting domains of differing density in supercooled water can be no more than nanoscale transient fluctuations.

Keywords:

• coarsening
• nucleation
• relaxation
• supercooled
• water

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. This argument presumes that reversible two-liquid behaviour requires interconversion without involvement of the crystal phase. Were ice to be an intermediate for interconversion between a low-density liquid and a high-density liquid, the bound discussed herein would not apply.

Additional information

Funding

In this work, David Chandler has been supported by the Director, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division and Chemical Sciences, Geosciences, and Biosciences Division under the US Department of Energy [contract number DE-AC02-05CH11231]. David T. Limmer has been supported by the Princeton Center for Theoretical Science.