Screening properties of Gaussian electrolyte models, with application to dissipative particle dynamics

TL;DR

This paper analyzes the screening behavior of Gaussian electrolyte models using simulations and theoretical methods, providing practical guidelines for mesoscale modeling in dissipative particle dynamics.

Contribution

It introduces a combined simulation and theoretical approach to understand screening in Gaussian electrolyte models and offers practical rules for mesoscale electrolyte modeling.

Findings

Screening length matches Debye length under certain conditions

Monte Carlo and RPA methods agree on screening properties

Practical rules-of-thumb for electrolyte modeling in DPD

Abstract

We investigate the screening properties of Gaussian charge models of electrolyte solutions by analysing the asymptotic behaviour of the pair distribution functions. We use a combination of Monte-Carlo simulations with the hyper-netted chain integral equation closure, and the random phase approximation, to establish the conditions under which a screening length is well defined and the extent to which it matches the expected Debye length. For practical applications, for example in dissipative particle dynamics, we are able to summarise our results in succinct rules-of-thumb which can be used for mesoscale modeling of electrolyte solutions. We thereby establish a solid foundation for future work, such as the systematic incorporation of specific ion effects.