Computer simulation of the structural effect of pressure on the hydrophobic hydration of methane
Computer simulation of the structural effect of pressure on the hydrophobic hydration of methane
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DOI：
10.1080/00268979909482943
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发表时间：
1999-01-10
影响因子：
1.7
通讯作者：
Mancera, RL
中科院分区：
文献类型：
--
作者：
Chau, PL;Mancera, RL
在压力分别为1100,200,400,800,1600atm和320k的条件下，对499个水分子中含有一种甲烷溶质的溶液进行了蒙特卡罗模拟。我们观察到，在任何压力下，水合壳水分子的氢键数目、近邻数目和四面体键序参数都比体积水分子少；然而，这些差异随着压力的增加而减小。在水合壳和体积中，压力的增加会使每个水分子的氢键和近邻数量增加，并伴随着四面体的增加。随着压力的增加，水氧-氧径向分布函数的第一个峰增加，表明水合壳水分子的结构增强。在低压下，甲烷周围会形成一个弱的第二水化壳层，只有在高压下，它才会变得越来越重要。
Monte Carlo simulations have been carried out on solutions containing one methane solute in 499 water molecules, at pressures of 1, 100, 200, 400, 800 and 1600 atm and 320 K. We observe that, at all pressures, hydration-shell water molecules have a smaller number of hydrogen bonds, a smaller number of near neighbours and larger tetrahedral bond-order parameters than bulk water molecules; however, these differences tend to decrease as pressure increases. In both the hydration shell and the bulk, the rise of pressure produces an increase in the number of hydrogen bonds and near neighbours per water molecule, accompanied by an increase in the tetrahedrality. Enhanced structuring of the hydration-shell water molecules is revealed by an increase of the first peak in the water oxygen-oxygen radial distribution function as pressure is increased. At low pressures, a weak second hydration shell around methane develops, and only at higher pressures does it become increasingly significant.