Abstract

The stability of spherical nanoclusters of methane and carbon dioxide hydrates in the environment of supercooled water has been studied by the molecular dynamics method under the isochoric and isobaric conditions. The process of system melting has been considered within a temperature range of 180–280 K and at pressures of 1, 50, and 100 atm (under isobaric conditions). It has been shown that clusters of CO₂ hydrate melt at temperatures lower than clusters of CH₄ hydrate do. The difference between the melting temperatures of the hydrates is about 40 K, which is explained by the higher solubility of carbon dioxide in water. The diffusion coefficients calculated for water and the gases attest to different mechanisms of melting their hydrates. The stability of the hydrates under the isochoric conditions appears to be lower than that under the isobaric conditions. For simulation under isobaric conditions, changes in the pressure and the degree of carbon dioxide filling have no effect on the position of the range of melting of hydrate nanoclusters.

中文翻译：

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甲烷和二氧化碳水合物球形纳米团簇稳定性的分子动力学模拟

摘要

在等压和等压条件下，通过分子动力学方法研究了甲烷和二氧化碳水合物球形纳米簇在过冷水环境中的稳定性。在180-280 K的温度范围内，以及在1、50和100 atm的压力下（在等压条件下），已经考虑了系统熔化的过程。结果表明，CO ₂水合物团簇在低于CH ₄团簇的温度下熔化水合吗。水合物的熔融温度之间的差异约为40 K，这可以通过二氧化碳在水中的较高溶解度来解释。为水和气体计算的扩散系数证明了其水合物融化的不同机理。在等压条件下，水合物的稳定性似乎低于等压条件下的稳定性。为了在等压条件下进行模拟，压力和二氧化碳填充程度的变化对水合物纳米团簇的熔化范围位置没有影响。