Rescic Jurij, Linse Per
Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia.
J Chem Phys. 2008 Sep 21;129(11):114505. doi: 10.1063/1.2971038.
The potential of mean force between two spherical and like-charged macroions in a salt-free aqueous solution has been determined using an extended primitive model and canonical Monte Carlo simulations. The systems considered covered the range from a purely repulsive to a purely attractive potential of mean force as the electrostatic coupling was increased. The macroions were modeled as spherical dielectric cavities, and the polarization surface charge densities occurring at the dielectric discontinuities were expanded in spherical harmonics. The surface polarization gave rise to (i) an attenuation of the counterion accumulation at the macroion surfaces at all cases considered, (ii) an enhanced repulsive potential of mean force in the weak to intermediate electrostatic coupling regime, and (iii) a less attractive at short separation and an enhanced attractive potential of mean force at longer macroion-macroion separation in the strong electrostatic coupling regime.
在无盐水溶液中，使用扩展原始模型和正则蒙特卡罗模拟确定了两个球形且带相同电荷的大离子之间的平均力势。随着静电耦合的增加，所考虑的系统涵盖了从纯排斥到纯吸引平均力势的范围。大离子被建模为球形介电腔，并且在介电不连续处出现的极化表面电荷密度用球谐函数展开。表面极化导致：（i）在所考虑的所有情况下，大离子表面反离子积累的衰减；（ii）在弱到中等静电耦合区域中，平均力的排斥势增强；（iii）在强静电耦合区域中，短距离时吸引力较小，而大离子 - 大离子分离距离较长时平均力的吸引力增强。
