Jiménez-Angeles Felipe, Odriozola Gerardo, Lozada-Cassou Marcelo
Programa de Ingeniería Molecular, Instituto Mexicano del Petróleo, Lázaro Cárdenas 152, 07730 México, Distrito Federal, México.
J Chem Phys. 2006 Apr 7;124(13):134902. doi: 10.1063/1.2178320.
A simple model for two like-charged parallel rods immersed in an electrolyte solution is considered. We derived the three point extension (TPE) of the hypernetted chain/mean spherical approximation (TPE-HNC/MSA) and Poisson-Boltzmann (TPE-PB) integral equations. We numerically solve these equations and compare them to our results of Monte Carlo (MC) simulations. The effective interaction force, F(T), the charge distribution profiles, rho(el)(x,y), and the angular dependent integrated charge function, P(theta), are calculated for this system. The analysis of F(T) is carried out in terms of the electrostatic and entropic (depletion) contributions, F(E) and F(C). We studied several cases of monovalent and divalent electrolytes, for which the ionic size and concentration are varied. We find good qualitative agreement between TPE-HNC/MSA and MC in all the cases studied. The rod-rod force is found to be attractive when immersed in large size, monovalent or divalent electrolytes. In general, the TPE-PB has poor agreement with the MC. For large monovalent and divalent electrolytes, we find angular dependent charge reversal charge inversion and polarizability. We discuss the intimate relationship between this angular dependent charge reversal and rod-rod attraction.
考虑了一个简单的模型，即两根带同种电荷的平行棒浸入电解质溶液中。我们推导了超网链/平均球近似（TPE-HNC/MSA）和泊松-玻尔兹曼（TPE-PB）积分方程的三点扩展（TPE）。我们对这些方程进行了数值求解，并将其与我们的蒙特卡罗（MC）模拟结果进行比较。计算了该系统的有效相互作用力F(T)、电荷分布轮廓rho(el)(x,y)以及角相关积分电荷函数P(theta)。根据静电和熵（耗尽）贡献F(E)和F(C)对F(T)进行了分析。我们研究了单价和二价电解质的几种情况，其中离子大小和浓度是变化的。我们发现在所有研究的情况下，TPE-HNC/MSA和MC之间在定性上有很好的一致性。发现当浸入大尺寸的单价或二价电解质中时，棒-棒力是吸引性的。一般来说，TPE-PB与MC的一致性较差。对于大尺寸的单价和二价电解质，我们发现了角相关的电荷反转和极化率。我们讨论了这种角相关电荷反转与棒-棒吸引之间的密切关系。
