Full-coordinate free-energy minimisation for complex molecular crystals

type I hydrates

Research output: Contribution to journalArticle

Abstract

A method is presented for efficient calculation of free energies for molecular crystals. The method is based on a generalisation of the local harmonic approximation. These calculations are rapid enough to allow optimisation of the free energy with respect to all atomic and crystallographic coordinates at finite temperatures for complex molecular crystals. The procedure has been illustrated for methane hydrate, which has about 150 atoms in the unit cell, and ice Ih. The resulting free energies of the fully optimised structures have been used to predict the conditions for three-phase equilibrium between methane hydrate, ice and methane gas, and shown to give results in excellent agreement with experiment.

Original languageEnglish
Pages (from-to)47-51
Number of pages5
JournalChemical Physics Letters
Volume262
Issue number1-2
DOIs
Publication statusPublished - 8 Nov 1996

Cite this

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title = "Full-coordinate free-energy minimisation for complex molecular crystals: type I hydrates",
abstract = "A method is presented for efficient calculation of free energies for molecular crystals. The method is based on a generalisation of the local harmonic approximation. These calculations are rapid enough to allow optimisation of the free energy with respect to all atomic and crystallographic coordinates at finite temperatures for complex molecular crystals. The procedure has been illustrated for methane hydrate, which has about 150 atoms in the unit cell, and ice Ih. The resulting free energies of the fully optimised structures have been used to predict the conditions for three-phase equilibrium between methane hydrate, ice and methane gas, and shown to give results in excellent agreement with experiment.",
author = "Westacott, {Robin Earle} and Rodger, {P M}",
year = "1996",
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language = "English",
volume = "262",
pages = "47--51",
journal = "Chemical Physics Letters",
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Full-coordinate free-energy minimisation for complex molecular crystals : type I hydrates. / Westacott, Robin Earle; Rodger, P M.

In: Chemical Physics Letters, Vol. 262, No. 1-2, 08.11.1996, p. 47-51.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Full-coordinate free-energy minimisation for complex molecular crystals

T2 - type I hydrates

AU - Westacott, Robin Earle

AU - Rodger, P M

PY - 1996/11/8

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N2 - A method is presented for efficient calculation of free energies for molecular crystals. The method is based on a generalisation of the local harmonic approximation. These calculations are rapid enough to allow optimisation of the free energy with respect to all atomic and crystallographic coordinates at finite temperatures for complex molecular crystals. The procedure has been illustrated for methane hydrate, which has about 150 atoms in the unit cell, and ice Ih. The resulting free energies of the fully optimised structures have been used to predict the conditions for three-phase equilibrium between methane hydrate, ice and methane gas, and shown to give results in excellent agreement with experiment.

AB - A method is presented for efficient calculation of free energies for molecular crystals. The method is based on a generalisation of the local harmonic approximation. These calculations are rapid enough to allow optimisation of the free energy with respect to all atomic and crystallographic coordinates at finite temperatures for complex molecular crystals. The procedure has been illustrated for methane hydrate, which has about 150 atoms in the unit cell, and ice Ih. The resulting free energies of the fully optimised structures have been used to predict the conditions for three-phase equilibrium between methane hydrate, ice and methane gas, and shown to give results in excellent agreement with experiment.

U2 - 10.1016/0009-2614(96)01042-1

DO - 10.1016/0009-2614(96)01042-1

M3 - Article

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SP - 47

EP - 51

JO - Chemical Physics Letters

JF - Chemical Physics Letters

SN - 0009-2614

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