Ⅰ型甲烷水合物晶体稳定性的分子动力学模拟

采用分子动力学方法,模拟了晶穴占有率和温度变化对I型甲烷水合物晶体稳定性的影响。通过考察晶体破坏过程中最终构象、均方位移、扩散系数、径向分布函数等分子的动力学和结构性质的变化,分析了分子动力学模拟中晶体结构失稳的微观特征,并提出了判断甲烷水合物晶体结构失稳的依据,这对水合物形成和分解过程的研究具有重要的参考价值。

Molecular dynamics simulation on the stability of structure Ⅰ methane hydrates

The key to whether or not methane hydrates can form or dissociate is the stability of the crystal structure. In this paper, the crystal stability of structure I methane hydrate is investigated using NPT molecular dynamics simulations, for a number of different temperatures and cage occupancies at P =30 bar. An eight unit-cell methane hydrate is employed as a model system. A series of different analyses are used to examine the microscopic molecular structure during the process of crystal corruption. These include snapshots of the final configurations, mean square displacements, diffusion coefficients, radial distribution functions and the distribution of tetra-hedral angles. As a result, these analyses are found to provide a distinct and quantificational characterization at a molecular level of the crystal corruption.