Thermodynamic stability of hydrogen hydrates of ice Ic and II structures

Lukman Hakim, Kenichiro Koga, Hideki Tanaka

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


The occupancy of hydrogen inside the voids of ice Ic and ice II, which gives two stable hydrogen hydrate compounds at high pressure and temperature, has been examined using a hybrid grand-canonical Monte Carlo simulation in wide ranges of pressure and temperature. The simulation reproduces the maximum hydrogen-to-water molar ratio and gives a detailed description on the hydrogen influence toward the stability of ice structures. A simple theoretical model, which reproduces the simulation results, provides a global phase diagram of two-component system in which the phase transitions between various phases can be predicted as a function of pressure, temperature, and chemical composition. A relevant thermodynamic potential and statistical-mechanical ensemble to describe the filled-ice compounds are discussed, from which one can derive two important properties of hydrogen hydrate compounds: the isothermal compressibility and the quantification of thermodynamic stability in term of the chemical potential.

Original languageEnglish
Article number144105
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number14
Publication statusPublished - Oct 13 2010

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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