Room temperature electrofreezing of water yields a missing dense ice phase in the phase diagram.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31028288.
- Also identified by DOI 10.1038/s41467-019-09950-z and PMC identifier 6486617.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
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 χ, 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 χ is an additional phase introduced to the state-of-the-art T-P phase diagram. The χ 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 χ is a rare polarized ferroelectric phase, whose nucleation/growth occurs only under very high electric fields.