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arXiv 1501.02495physics.chem-ph
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分子理论和溶质吸引力对疏水相互作用的影响

Molecular theory and the effects of solute attractive forces on hydrophobic interactions

M. I. Chaudhari, S. B. Rempe, D. Asthagiri, L. Tan, L. R. Pratt

摘要:

通过理论和模拟结果的协调发展,研究了溶质吸引力对疏水相互作用的影响。我们提出了一个简明的推导局部分子场(LMF)理论的溶质吸引力对疏水相互作用的影响,推导澄清了LMF理论的密切关系,EXP近似很久以前应用到这个问题。模拟结果表明,从纯粹的排斥原子溶质相互作用,包括现实的吸引相互作用\emph{diminishes}的疏水键的强度的变化。对于Ar-Ar rdfs考虑逐点,溶质吸引力对疏水相互作用的影响的数值结果是相反的符号和更大的幅度比预测的LMF理论。从准化学理论的角度讨论了这种比较,并建议这种差异的第一个原因是在LMF理论的Ar对的水化能的不完整的评估。与最近的建议所需的关联函数积分的系统大小外推,Ar-Ar rdfs允许渗透第二维里系数$B_2$的评价。这些$B_2$还表明,引入吸引相互作用导致更积极的(排斥)值。在吸引相互作用的作用下,随着温度的升高,$B_2$可以从正值变为负值。这与Watanabe,\emph{et al.,}的历史工作一致,$B_2 \approx 0$用于中间情况。在这里的所有情况下,随着温度的升高,$B_2$变得更有吸引力。

英文摘要:

The role of solute attractive forces on hydrophobic interactions is studied by coordinated development of theory and simulation results for Ar atoms in water. We present a concise derivation of the local molecular field (LMF) theory for the effects of solute attractive forces on hydrophobic interactions, a derivation that clarifies the close relation of LMF theory to the EXP approximation applied to this problem long ago. The simulation results show that change from purely repulsive atomic solute interactions to include realistic attractive interactions \emph{diminishes} the strength of hydrophobic bonds. For the Ar-Ar rdfs considered pointwise, the numerical results for the effects of solute attractive forces on hydrophobic interactions are of opposite sign and larger in magnitude than predicted by LMF theory. That comparison is discussed from the point of view of quasi-chemical theory, and it is suggested that the first reason for this difference is the incomplete evaluation within LMF theory of the hydration energy of the Ar pair. With a recent suggestion for the system-size extrapolation of the required correlation function integrals, the Ar-Ar rdfs permit evaluation of osmotic second virial coefficients $B_2$. Those $B_2$ also show that incorporation of attractive interactions leads to more positive (repulsive) values. With attractive interactions in play, $B_2$ can change from positive to negative values with increasing temperatures. This is consistent with the historical work of Watanabe, \emph{et al.,} that $B_2 \approx 0$ for intermediate cases. In all cases here, $B_2$ becomes more attractive with increasing temperature.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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