PNNL

Abstract

The phenomena of underscreening in electrolyte solutions has found a resurgence of both theoretical and experimental interest in chemical physics community. In order to systematically understand and investigate this phenomena in electrolytes requires a theory of concentrated electrolytes to describe charge-charge correlations beyond the Debye-H\"uckel (DH) theory. We review the history of the theory of electrolytes that can transition from the DH limit to concentrations where charge correlations dominate giving rise to underscreening and the associated Kirkwood Transitions. In this perspective we provide a novel conceptual approach to a theoretical formulation of electrolyte solutions that exploits the competition between a molecular informed short-range (SR) and long-range (LR) interactions provided by a simple dielectric theory. The salient picture of our approach allows us to capture deviations from DH with a single unknown function that can be readily computed with the tools of molecular simulation. In addition we demonstrate how to apply this theory to understand both realistic molecular models and modern small angel X-ray scattering (SAXS) experiments of electrolytes. The resulting formulation provides an accurate picture of the collective phenomenon of screening in concentrated electrolytes.