PNNL

Abstract

In addition to its scientific significance, the distribution of ions in the bulk and at aqueous interfaces also is very important for practical reasons. A quantitative description of the ionic distribution and how to describe interactions between them in different environments remain a challenge are the subjects of current debate. In this study, we found that interionic potentials of mean force (PMF) and interfacial properties are very sensitive to the ion-ion interaction potential models. Our computed Sr2+-Cl- PMF shows a no contact ion-pair state and a shallow solvent-separated ion-pair state. In addition, we were able to quantitatively capture the experimental x-ray reflectivity results of the aqueous salt interface of Sr2+-Cl- ion-pair system, and predict the reflectivity for Sr2+-Br- and Sr2+-I- systems. In this paper, we provide a detailed physical description of the interfacial structure of these systems.. This work was supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences (BES), Division of Chemical Sciences, Geosciences and Biosciences. Pacific Northwest National Laboratory is a multiprogram national laboratory operated for DOE by Battelle.