Structures and phase transitions of amorphous ices

Ichiro Okabe, Hideki Tanaka, Koichiro Nakanishi

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

Molecular dynamics simulations have been carried out in order to clarify the structural and hydrogen bond network differences among high density amorphous ice (HDA), low density amorphous ice (LDA), and hexagonal ice (ice [Formula Presented]). Ice [Formula Presented] is transformed to HDA at 1.27 GPa and 77 K. A very long time (order of a nanosecond) to complete the transition is required. It is found that molecular motions are delocalized in the early stage and become localized in the final stage of the relaxation. LDA is obtained by heating HDA to 160 K. The second peak of the radial distribution function is more clearly separated from the first peak in LDA than in HDA. Few bifurcated hydrogen bonds are found in LDA compared with HDA, which is evidence that LDA resembles crystal ice in short range order. The network topology of the system is also analyzed in terms of the distribution of Voronoi polyhedra, where the density lies between stable HDA and LDA. Density fluctuations are found, which should be attributed to the precursor of a phase separation between HDA and LDA.

Original languageEnglish
Pages (from-to)2638-2647
Number of pages10
JournalPhysical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics
Volume53
Issue number3
DOIs
Publication statusPublished - Jan 1 1996
Externally publishedYes

ASJC Scopus subject areas

  • Statistical and Nonlinear Physics
  • Statistics and Probability
  • Condensed Matter Physics

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