中国物理B ›› 2001, Vol. 10 ›› Issue (10): 958-965.doi: 10.1088/1009-1963/10/10/314

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

NEUTRON SCATTERING AND LATTICE DYNAMICAL STUDIES OF THE HIGH-PRESSURE PHASE ICE (II)

董顺乐1, 王燕2   

  1. (1)Department of Physics, Ocean University of Qingdao, Qingdao 266003, China; (2)Department of Physics, UMIST, P.O. Box 88, Manchester, M 60 1QD, United Kingdom
  • 收稿日期:2001-01-07 修回日期:2001-05-19 出版日期:2005-06-12 发布日期:2005-06-12
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 10144001).

NEUTRON SCATTERING AND LATTICE DYNAMICAL STUDIES OF THE HIGH-PRESSURE PHASE ICE (II)

Dong Shun-le (董顺乐)a, Wang Yan (王燕)b   

  1. a Department of Physics, Ocean University of Qingdao, Qingdao 266003, China; b Department of Physics, UMIST, P.O. Box 88, Manchester, M 60 1QD, United Kingdom
  • Received:2001-01-07 Revised:2001-05-19 Online:2005-06-12 Published:2005-06-12
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 10144001).

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摘要： Lattice dynamical calculations have been carried out for ice II based on the force field constructed for ice Ih. In order to fully understand ice II inelastic neutron scattering spectra, the decomposed phonon density of states was shown mode by mode. Calculated results have shown that the hydrogen bond force constant between the six-molecule rings is significantly weaker, 75eV/nm2, compared with the force constant, 220eV/nm2, within the rings. Inelastic neutron scattering spectra of clathrate hydrate H2O+He are almost the same as ice II. This means that the absorption of He atoms cannot affect the bond strengths of the ice II host lattice. Based on the force field model for ice II, the van der Waals interactions between water molecules and helium atoms are considered. The results obtained are consistent with experimental data. Lattice dynamical calculations have been carried out for ice II using seven rigid pairwise potentials. It was found that MCY makes the stretching and bending interactions in ice II too weak and makes the O-O bond length too long (～5%), thus its lattice densities are obviously lower than other potential lattices or experimental values.

Abstract: Lattice dynamical calculations have been carried out for ice II based on the force field constructed for ice Ih. In order to fully understand ice II inelastic neutron scattering spectra, the decomposed phonon density of states was shown mode by mode. Calculated results have shown that the hydrogen bond force constant between the six-molecule rings is significantly weaker, 75eV/nm2, compared with the force constant, 220eV/nm2, within the rings. Inelastic neutron scattering spectra of clathrate hydrate H2O+He are almost the same as ice II. This means that the absorption of He atoms cannot affect the bond strengths of the ice II host lattice. Based on the force field model for ice II, the van der Waals interactions between water molecules and helium atoms are considered. The results obtained are consistent with experimental data. Lattice dynamical calculations have been carried out for ice II using seven rigid pairwise potentials. It was found that MCY makes the stretching and bending interactions in ice II too weak and makes the O-O bond length too long (～5%), thus its lattice densities are obviously lower than other potential lattices or experimental values.

Key words: inelastic neutron scattering, phonon density of states, lattice dynamics

中图分类号:  (Phonon states and bands, normal modes, and phonon dispersion)

  • 63.20.D-
61.50.Lt (Crystal binding; cohesive energy)