中国物理B ›› 2018, Vol. 27 ›› Issue (4): 43103-043103.doi: 10.1088/1674-1056/27/4/043103

• TOPIC REVIEW—Thermal and thermoelectric properties of nano materials • 上一篇    下一篇

Density functional theory study of structural stability for gas hydrate

Ping Guo(郭平), Yi-Long Qiu(邱奕龙), Long-Long Li(李龙龙), Qiang Luo(罗强), Jian-Fei Zhao(赵建飞), Yi-Kun Pan(潘意坤)   

  1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China
  • 收稿日期:2017-12-06 修回日期:2018-01-23 出版日期:2018-04-05 发布日期:2018-04-05
  • 通讯作者: Yi-Long Qiu E-mail:qiuyl0328@foxmail.com
  • 基金资助:

    Project supported by the National Key Research and Development Program of China (Grant No. 2016YFC0304008).

Density functional theory study of structural stability for gas hydrate

Ping Guo(郭平), Yi-Long Qiu(邱奕龙), Long-Long Li(李龙龙), Qiang Luo(罗强), Jian-Fei Zhao(赵建飞), Yi-Kun Pan(潘意坤)   

  1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China
  • Received:2017-12-06 Revised:2018-01-23 Online:2018-04-05 Published:2018-04-05
  • Contact: Yi-Long Qiu E-mail:qiuyl0328@foxmail.com
  • Supported by:

    Project supported by the National Key Research and Development Program of China (Grant No. 2016YFC0304008).

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摘要：

Using the first-principles method based on the density functional theory (DFT), the structures and electronic properties of different gas hydrates (CO2, CO, CH4, and H2) are investigated within the generalized gradient approximation. The structural stability of methane hydrate is studied in this paper. The results show that the carbon dioxide hydrate is more stable than the other three gas hydrates and its binding energy is -2.36 eV, and that the hydrogen hydrate is less stable and the binding energy is -0.36 eV. Water cages experience repulsion from inner gas molecules, which makes the hydrate structure more stable. Comparing the electronic properties of two kinds of water cages, the energy region of the hydrate with methane is low and the peak is close to the left, indicating that the existence of methane increases the stability of the hydrate structure. Comparing the methane molecule in water cages and a single methane molecule, the energy of electron distribution area of the former is low, showing that the filling of methane enhances the stability of hydrate structure.

关键词: first principles, gas hydrate, binding energy, stability

Abstract:

Using the first-principles method based on the density functional theory (DFT), the structures and electronic properties of different gas hydrates (CO2, CO, CH4, and H2) are investigated within the generalized gradient approximation. The structural stability of methane hydrate is studied in this paper. The results show that the carbon dioxide hydrate is more stable than the other three gas hydrates and its binding energy is -2.36 eV, and that the hydrogen hydrate is less stable and the binding energy is -0.36 eV. Water cages experience repulsion from inner gas molecules, which makes the hydrate structure more stable. Comparing the electronic properties of two kinds of water cages, the energy region of the hydrate with methane is low and the peak is close to the left, indicating that the existence of methane increases the stability of the hydrate structure. Comparing the methane molecule in water cages and a single methane molecule, the energy of electron distribution area of the former is low, showing that the filling of methane enhances the stability of hydrate structure.

Key words: first principles, gas hydrate, binding energy, stability

中图分类号:  (Applications of density-functional theory (e.g., to electronic structure and stability; defect formation; dielectric properties, susceptibilities; viscoelastic coefficients; Rydberg transition frequencies))

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