论文标题
了解疏水溶剂的物理学
Understanding the physics of hydrophobic solvation
论文作者
论文摘要
在扩展的疏水球形溶质附近的水模拟显示出存在耗尽密度和伴随增强密度波动的区域。这两种现象的物理起源都保持晦涩难懂。我们研究了这些效果，采用介观势分析，简单的Lennard-Jones（LJ）溶剂和大规范的Monte Carlo（GCMC）模拟的经典密度功能理论（DFT）计算。我们认为，密度耗竭和增强的波动是近乎危险的现象。具体而言，我们表明它们可以被视为临界干燥表面过渡的残余物，该残留物发生在宏观平面极限中的散装液体蒸气共存，即作为溶质半径$ r_s \ to \ infty $。关注径向密度曲线$ρ（r）$和对波动的敏感空间度量，局部可压缩概况$χ（r）$，我们的约束力分析为$ρ（r）$和$χ（r）$ scale的关键特征$ r_s $ r_s $ r_S $ r_ sfs anf and sf and sfs and sfs and sf and sf and sf and sf and sf asf and sf and vernon and sf and vernon and vernon and vancon and vernon和化学电位的液体蒸气共存，$Δμ$。这些缩放预测通过我们的DFT计算和GCMC模拟确认。因此，我们的理论为理解疏水溶剂化的物理学提供了坚定的基础。
Simulations of water near extended hydrophobic spherical solutes have revealed the presence of a region of depleted density and accompanying enhanced density fluctuations.The physical origin of both phenomena has remained somewhat obscure. We investigate these effects employing a mesoscopic binding potential analysis, classical density functional theory (DFT) calculations for a simple Lennard-Jones (LJ) solvent and Grand Canonical Monte Carlo (GCMC) simulations of a monatomic water (mw) model. We argue that the density depletion and enhanced fluctuations are near-critical phenomena. Specifically, we show that they can be viewed as remnants of the critical drying surface phase transition that occurs at bulk liquid-vapor coexistence in the macroscopic planar limit, i.e.~as the solute radius $R_s\to\infty$. Focusing on the radial density profile $ρ(r)$ and a sensitive spatial measure of fluctuations, the local compressibility profile $χ(r)$, our binding potential analysis provides explicit predictions for the manner in which the key features of $ρ(r)$ and $χ(r)$ scale with $R_s$, the strength of solute-water attraction $\varepsilon_{sf}$, and the deviation from liquid-vapor coexistence of the chemical potential, $δμ$. These scaling predictions are confirmed by our DFT calculations and GCMC simulations. As such our theory provides a firm basis for understanding the physics of hydrophobic solvation.
