Free Energy, Entropy and Heat Capacity of the Hydrophobic Interaction as a Function of Pressure
Free Energy, Entropy and Heat Capacity of the Hydrophobic Interaction as a Function of Pressure
复制标题
疏水相互作用的自由能、熵和热容与压力的关系
DOI：
10.1021/jp000841s
复制
发表时间：
2000
影响因子：
3.3
通讯作者：
S. Rick
中科院分区：
文献类型：
--
作者：
S. Rick
分子动力学模拟的甲烷对在水中被用来计算的疏水相互作用的压力的函数的热力学性质。发现压力可以降低形成甲烷聚集体的趋势。熵对自由能的贡献在大气压下极大地稳定聚集，是高度压力依赖的。随着压力的增加，熵稳定性稳定下降，直到在7千巴，接触对的熵等于溶剂分离对的熵。的接触和溶剂分离对之间的热容量变化被证明是大的和积极的，在1个大气压，疏水过程的特点。在较高的压力下，热容变化为零，表明疏水效应的两个重要性质，即大的熵降低和热容增加在高压下丧失。自由能、体积和熵的变化与相应的变化是一致的。
Molecular dynamics simulations of a methane pair in water are used to calculate the thermodynamic properties of the hydrophobic interaction as a function of pressure. Pressure is found to decrease the tendency to form methane aggregates. The entropic contribution to the free energy, which at atmospheric pressure greatly stabilizes aggregation, is highly pressure dependent. As the pressure increases, the entropic stabilization steadily decreases until, at 7 kbar, the entropy of the contact pair is equal to the entropy of the solvent separated pair. The heat capacity change between the contact and solvent separated pair is shown to be large and positive at 1 atm, as is characteristic of hydrophobic processes. At higher pressures, the heat capacity change is zero, indicating that two of the significant properties of the hydrophobic effect, the large entropy decrease and heat capacity increase are lost at high pressures. The free energy, volume and entropy changes are consistent with the corresponding changes...