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
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)
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)
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.
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))