Beyond Poisson-Boltzmann: Numerical Sampling of Charge Density Fluctuations

作者：Poitevin Frederic^*; Delarue Marc; Orland Henri

来源：Journal of Physical Chemistry B, 2016, 120(26): 6270-6277.

DOI：10.1021/acs.jpcb.6b02650

We present a method aimed at sampling charge density fluctuations in Coulomb systems. The derivation follows from a functional integral representation of the partition function in terms of charge density fluctuations. Starting from the mean-field solution given by the Poisson-Boltzmann equation, an original approach is proposed to numerically sample fluctuations around it, through the propagation of a Langevin-like stochastic partial differential equation (SPDE). The diffusion tensor of the SPDE can be chosen so as to avoid the numerical complexity linked to long-range Coulomb interactions, effectively rendering the theory completely local. A finite-volume implementation of the SPDE is described, and the approach is illustrated with preliminary results on the study of a system made of two like-charge ions immersed in a bath of counterions.

• 出版日期2016-7-7
• 单位中国地震局; 北京计算科学研究中心