Room temperature electrofreezing of water yields a missing dense ice phase in the phase diagram.

ABSTRACT: Water can freeze into diverse ice polymorphs depending on the external conditions such as temperature (T) and pressure (P). Herein, molecular dynamics simulations show evidence of a high-density orthorhombic phase, termed ice ?, forming spontaneously from liquid water at room temperature under high-pressure and high external electric field. Using free-energy computations based on the Einstein molecule approach, we show that ice ? is an additional phase introduced to the state-of-the-art T-P phase diagram. The ? phase is the most stable structure in the high-pressure/low-temperature region, located between ice II and ice VI, and next to ice V exhibiting two triple points at 6.06?kbar/131.23?K and 9.45?kbar/144.24?K, respectively. A possible explanation for the missing ice phase in the T-P phase diagram is that ice ? is a rare polarized ferroelectric phase, whose nucleation/growth occurs only under very high electric fields.

SUBMITTER: Zhu W 

PROVIDER: S-EPMC6486617 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature