Thermodynamic properties of methane/water interface predicted by molecular dynamics simulations.
Thermodynamic properties of methane/water interface predicted by molecular dynamics simulations.
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DOI：
10.1063/1.3579480
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发表时间：
2011-04
期刊：
影响因子：
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通讯作者：
Ryuji Sakamaki;A. Sum;T. Narumi;R. Ohmura;K. Yasuoka
中科院分区：
文献类型：
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作者：
Ryuji Sakamaki;A. Sum;T. Narumi;R. Ohmura;K. Yasuoka
采用TIP4P/2005和SPC/E两种不同的水模型和两套结合规则，对甲烷/水界面的热力学性质进行了分子动力学模拟。计算了各种压力条件下的密度分布、界面张力、表面过剩、表面压力和共存密度。采用TIP4P/2005水模型，水和甲烷的最佳结合规则与溶解度相适应，对界面性质进行了较好的预测。通过比较不同方法得到的表面压力，考察了无限稀释近似用于计算界面张力的表面过剩。结果表明，甲烷溶解度随压力的变化和界面甲烷密度分布最大值的位置与压力无关，最大压力约为2 Mpa。我们还计算了吸附热焓和吸附熵，以描述吸附的温度依赖性。
Molecular dynamics simulations have been performed to examine the thermodynamic properties of methane/water interface using two different water models, the TIP4P/2005 and SPC/E, and two sets of combining rules. The density profiles, interfacial tensions, surface excesses, surface pressures, and coexisting densities are calculated over a wide range of pressure conditions. The TIP4P/2005 water model was used, with an optimized combining rule between water and methane fit to the solubility, to provide good predictions of interfacial properties. The use of the infinite dilution approximation to calculate the surface excesses from the interfacial tensions is examined comparing the surface pressures obtained by different approaches. It is shown that both the change of methane solubilities in pressure and position of maximum methane density profile at the interface are independent of pressure up to about 2 MPa. We have also calculated the adsorption enthalpies and entropies to describe the temperature dependency of the adsorption.