The fate of deeply supercooled liquid water has been the topic of intense research and fruitful disputes. The heat capacity and compressibility of liquid water increase in the supercooled region, apparently following a power law that would diverge at about 228 K, just below the experimental temperature of homogeneous nucleation of ice, TH = 232 K. Fast ice crystallization has prevented the experimental characterization of the structure and thermodynamics of liquid water at temperatures between 140 and 232 K, a region known as water's �no-man's land�. Due to the slow dynamics of supercooled water, this region is very challenging to investigate with atomistic simulations. We used molecular simulations with an efficient and accurate coarse-grained model of water to investigate the relationship between the structure, anomalies and crystallization rate of water and to elucidate the fate of liquid water in �no-man's land�.1,2,3 The simulations indicate that the continuous structural transformation of liquid water into a four-coordinated liquid is responsible for the thermodynamic anomalies of liquid water and also controls the crystallization rate. The simulations predict that the crystallization rate of water reaches a maximum at a temperature Tx just below TH, a result that is also supported by calculations using classical nucleation theory with experimental free energy and diffusivity data for water. The maximum crystallization rate at Tx is due to a crossover between a nucleation-dominated regime (above Tx) and a growth-dominated regime (below Tx). At temperatures below Tx = 225 K, liquid water cannot be equilibrated because the time scale of crystallization is comparable to the time scale of relaxation of the liquid. This implies that bulk supercooled water reaches a kinetic limit of metastability on entering into �no-man's land�.1. Moore, E. B. & Molinero, V. Structural transformation in supercooled water controls the crystallization rate of ice. Nature 479 , 506�508 (2011).2. Moore, E. B. & Molinero, V. Ice crystallization in water's 'no-man's land'. J Chem Phys 132 , 244504 (2010).3. Xu, L. & Molinero, V. Is there a liquid-liquid transition in confined water? The Journal of Physical Chemistry B 115 , 14210�14216 (2011).

Kinetic limit of metastability of supercooled water

244th National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.