Structure and phase behavior of high-density ice from molecular-dynamics simulations with the ReaxFF potential

Yuji Adachi, Kenichiro Koga

Research output: Contribution to journalArticlepeer-review

Abstract

We report a molecular dynamics simulation study of dense ice modeled by the reactive force field (ReaxFF) potential, focusing on the possibility of phase changes between crystalline and plastic phases as observed in earlier simulation studies with rigid water models. It is demonstrated that the present model system exhibits phase transitions, or crossovers, among ice VII and two plastic ices with face-centered cubic (fcc) and body-centered cubic (bcc) lattice structures. The phase diagram derived from the ReaxFF potential is different from those of the rigid water models in that the bcc plastic phase lies on the high-pressure side of ice VII and does the fcc plastic phase on the low-pressure side of ice VII. The phase boundary between the fcc and bcc plastic phases on the pressure, temperature plane extends to the high-temperature region from the triple point of ice VII, fcc plastic, and bcc plastic phases. Proton hopping, i.e., delocalization of a proton, along between two neighboring oxygen atoms in dense ice is observed for the ReaxFF potential but only at pressures and temperatures both much higher than those at which ice VII-plastic ice transitions are observed.

Original languageEnglish
Article number114501
JournalJournal of Chemical Physics
Volume153
Issue number11
DOIs
Publication statusPublished - Sep 21 2020

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Fingerprint Dive into the research topics of 'Structure and phase behavior of high-density ice from molecular-dynamics simulations with the ReaxFF potential'. Together they form a unique fingerprint.

Cite this