Poisson–Boltzmann theory with non-linear ion correlations. (17th June 2019)

• Record Type: Journal Article
• Authors: Su, Mao; Xu, Zhijie; Wang, Yanting
• Is Part Of: Journal of physics. Volume 31:Number 35(2019)
• Publication Date: 2019-06-17
• Subjects: PB theory -- correlations -- self-energy; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/ab24a9
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: The Poisson–Boltzmann (PB) theory is widely used to depict ionic systems. As a mean-field theory, the PB theory neglects the correlation effect in the ionic atmosphere and leads to deviations from experimental results as the concentration or charge valance increases. A modified PB theory including ion correlation effect while retaining its simplicity is critical for many important applications in which ion correlation effect can be significant. In this paper, we present a new model to incorporate ion correlations into the original PB equation by utilizing the Green's function with a non-linear form of the self-energy, which is different from the linear self-energy equation obtained by the field-theoretic (FT) approach. Both equations are solved numerically and compared with our molecular dynamics (MD) simulation. The co-ion distribution calculated by the FT approach deviates significantly from the MD simulation, while our results for both counter-ion and co-ion distributions are justified by the MD simulation.