Tan Zhi-Jie, Chen Shi-Jie
Department of Physics and Astronomy and Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA.
J Chem Phys. 2005 Jan 22;122(4):44903. doi: 10.1063/1.1842059.
A statistical mechanical model is presented which explicitly accounts for the fluctuations, the electrostatic, and the excluded volume correlations for ions bound to a polyelectrolyte such as DNA. The method can be employed to treat a wide range of ionic conditions including multivalent ions. The microscopic framework of the theory permits the use of realistic finite length and grooved structural model for the polyelectrolyte and modeling of the finite size of the bound ions. Test against Monte Carlo simulations suggests that the theory can give accurate predictions for the ion distribution and the thermodynamic properties. For multivalent ions, the theory makes improved predictions as compared with the mean-field approach. Moreover, for long polyelectrolyte and dilute salt concentration, the theory predicts ion binding properties that agree with the counterion condensation theory.
提出了一种统计力学模型，该模型明确考虑了与诸如DNA等聚电解质结合的离子的涨落、静电和排除体积相关性。该方法可用于处理包括多价离子在内的各种离子条件。该理论的微观框架允许使用聚电解质的实际有限长度和带槽结构模型，并对结合离子的有限尺寸进行建模。与蒙特卡罗模拟的对比测试表明，该理论可以对离子分布和热力学性质给出准确的预测。对于多价离子，与平均场方法相比，该理论给出了改进的预测。此外，对于长聚电解质和稀盐浓度，该理论预测的离子结合性质与反离子凝聚理论一致。
