电解质水溶液传递性质的布朗动力学模拟研究

在传统布朗动力学的基础上, 考虑流体力学的影响, 并且引入Smart Monte Carlo方法的接受概率, 对电解质溶液进行布朗动力学模拟, 得到不同浓度和温度下KCl溶液中离子间的径向分布函数, 并且与超网链积分方程理论计算结果进行了比较, 同时, 模拟了KCl和NaCl溶液的摩尔电导率. 模拟过程基于电解质溶液的原始模型, 溶剂被看作连续介质, 溶质分子之间的相互作用采用软核加静电的势能函数模型, 长程静电力的处理采用Ewald加和方法. 结果显示, 流体力学的作用对于电解质溶液的结构性质没有明显的影响, 但是对于传递性质的影响显著; 考虑流体力学作用的布朗动力学模拟结果与实验数据吻合良好.

Study on the Transport Properties of Aqueous Electrolyte Solution by Brownian Dynamics Simulation

Brownian dynamics simulation was carried out to study the electrolyte solution. The effect of hydrodynamic interactions was taken into account and an acceptance criterion known from the Smart Monte Carlo method was combined with the traditional method. The radial distribution functions for both like and unlike-ion interactions were calculated at different concentration and temperature and compared with those from HNC integral equation. The molar conductivity of sodium chloride and potassium chloride aqueous solution was also obtained and compared with the experiment values. In our simulation, the sol- vent-averaged interaction potential between the ions was modeled by pairwise repulsive soft-core interac- tions and Coulomb forces that were handled by Ewald summation technique. It is found that the hydrody- namic interactions have no effect on the structure properties in contrast with an obvious effect on transport- ing properties. Good agreement between simulation results and the corresponding values from experiment was achieved by including hydrodynamic interactions.