Department of Chemistry, University of Houston, Houston, Texas 77204-5003, USA.
J Phys Chem B. 2010 May 13;114(18):6074-83. doi: 10.1021/jp9108865.
A renormalization of the 3D-RISM-HNC integral equation is used to study the solvent and ion distributions at neutral and negatively charged planar atomistic surfaces. The charge density of the surfaces ranged from 0.0 to 0.4116 C/m(2), and the modeled electrolyte solutions consist of the salts NaCl, KCl, and CsCl at concentrations of 0.1, 0.25, and 1.0 M in SPC/E water. The results are qualitatively compared to the results from other integral equation methods and simulations for similar models. We find that the 3D-IEs predict an electric multilayer screening behavior in the solvent and ion distributions in contrast to the double layer anticipated from Poisson-Boltzmann theory. It is observed that the cation size has a significant effect on the distributions near the surface up to three solvation layers beyond which the behavior is the same among the different cations. The response of the distributions to the charged surface is described as an increase in ion and solvent density near the wall. The higher concentration solutions screen the electrostatic source more strongly at the wall as expected. The importance of ion-solvent and ion-ion correlations near the surface is shown through three-body correlation functions which are obtainable from the 3D-IEs in this study.
采用 3D-RISM-HNC 积分方程的重整化来研究中性和带负电荷的平面原子表面处的溶剂和离子分布。表面的电荷密度范围为 0.0 至 0.4116 C/m(2)，所模拟的电解质溶液由 SPC/E 水中的盐 NaCl、KCl 和 CsCl 组成，浓度分别为 0.1、0.25 和 1.0 M。将结果与类似模型的其他积分方程方法和模拟的结果进行定性比较。我们发现 3D-IEs 预测了溶剂和离子分布中的电多层屏蔽行为，与泊松-玻尔兹曼理论所预期的双层相反。观察到阳离子尺寸对表面附近的分布有显著影响，在超过三个溶剂化层后，不同阳离子的行为相同。分布对带电表面的响应被描述为壁附近离子和溶剂密度的增加。正如预期的那样，较高浓度的溶液在壁处更强烈地屏蔽静电源。通过本研究中可从 3D-IEs 获得的三体相关函数，表明了表面附近离子-溶剂和离子-离子相关的重要性。
