密度泛函理论研究高价离子在纳米孔内的结构  

Density functional theory study on structures of high-valent ion inside nanopores

作　　者：彭勃[1] 于养信[1] 

机构地区：[1]清华大学化学工程系,化学工程联合国家重点实验室,北京100084

出　　处：《中国科技论文在线》2009年第12期900-904,共5页

基　　金：高等学校博士学科点专项科研基金(20070003099);国家自然科学基金(20676065)

摘　　要：电解质溶液中离子在主体相与纳米孔间的分配及其在纳米孔内的结构,不但对纳滤膜分离非常重要,而且还有助于理解生物离子通道的特性。因此,利用部分微扰密度泛函理论,预测了3∶3型电解质溶液中离子在带电纳米孔内的离子密度分布和静电势分布,发现高价阴阳离子密度分布曲线有交叉现象,静电势也呈现为震荡曲线。这些现象与分子模拟结果符合得很好,而传统的Poisson-Boltzmann方程却不能预测这种现象。对混合电解质溶液MX2-NX-H2O的结果同样表明本文的部分微扰的密度泛函理论要好于传统的Poisson-Boltzmann方程,且能够预测高价离子在带电纳米孔内的结构与分配。The structure and ion-partitioning of electrolyte solution in charged nanopores are not only very important for the nanofiltration separation,but also helpful for us to understand the biological functions of ion channels. The ion density distributions and electrostatic potentials of 3∶3 electrolyte solutions in a charged cylindrical nanopore are predicted using the partially perturbative density functional theory. The calculated results show that there are crosses between counterion and coion density profiles,and the electrostatic potential curve performs as an oscillatory curve. The calculated results are in excellent agreement with the corresponding Monte Carlo simulation data. In contrast,the traditional Poisson-Boltzmann equation cannot predict these phenomena. Further application of the partially perturbative density functional theory to MX2-NX-H2O solution indicates that the present theory is better than the Poisson-Boltzmann equation and can be used to predict the structures and ion-partitioning of high-valent ions in charged nanopores.

关 键 词：电解质溶液 高价离子 带电纳米孔 密度泛函理论 离子密度分布 离子分配 

分 类 号：O646[理学—物理化学]