Effect of relaxing the continuum dielectric approximation on Poisson-Boltzmann thermodynamics

Abstract

In this study a critical evaluation of the consequences of relaxing the continuum dielectric approximation within the framework of Poisson-Boltzmann theory is presented. Three models are constructed to describe possible variations of the permittivity with respect to the distance from a central ion, and the sensitivity of the calculated potentials to the parameters of these models is investigated. Following this, the criteria of Onsager (internal consistency), Frank and Thompson (‘fine-grainedness of the ion atmosphere’) and Stillinger and Lovett (the second-moment condition) are applied to assess the quality of the results obtained. Finally, activity coefficients for a McMillan-Mayer system are calculated and compared with results obtained in other studies. Conclusions based on these calculations are drawn, and an attempt is made to place the study within the context of recent developments in electrolyte theory.

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Notes on contributors

Donald G. Knox

This work is based on a dissertation submitted in partial fulfilment of the requirements for the Ph.D. degree at the University of Notre Dame.