Thermodynamics of the Hydration Shell. 2. Excess Volume and Compressibility of a Hydrophobic Solute
Thermodynamics of the Hydration Shell. 2. Excess Volume and Compressibility of a Hydrophobic Solute
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水合壳的热力学。
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
R. Levy
中科院分区：
文献类型：
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作者：
Nobuyuki Matubayasi and;R. Levy
研究了超额体积和可压缩性的水化壳模型。提出了一个适用于正则系综的修正的Kirkwood−Buff超额体积公式。其压力导数为过量压缩系数，可表示为水化壳层上局部溶剂压缩系数的积分。对于甲烷在水中的第一种应用，通过蒙特卡罗模拟计算了局部溶剂密度和溶质周围的可压缩性，它们是离溶质距离的连续函数。根据局部溶剂密度和压缩系数与体积值的偏差，分析了超额体积和压缩系数在水化壳层内的局部化。对于过剩体积，还描述了溶剂分子被溶质排除的影响。溶液的排除体积效应约占总超额体积的80%。
The hydration shell model for the excess volume and compressibility is examined. A modified Kirkwood−Buff formula for the excess volume, which is appropriate for use in the canonical ensemble, is presented. Its pressure derivative is shown to be the excess compressibility, which can be expressed as an integral of the local solvent compressibility over the hydration shell. For methane in water, which is chosen as the first application, the local solvent density and compressibility around the solute are calculated from a Monte Carlo simulation as continuous functions of the distance from the solute. The localization of the excess volume and compressibility within the hydration shell is then analyzed in terms of the deviation of the local solvent density and compressibility from their bulk values, respectively. The effect of the exclusion of solvent molecules by the solute is also described for the excess volume. About 80% of the total excess volume is accounted for by the excluded volume effect of the solut...