The Influence of Liquid Structure on Interfacial Ion Distributions
Department of Chemical Engineering, University of Illinois Chicago
Jeudi 21/06/2007, 11:00
NIMBE Bât 125, p.157, CEA-Saclay
Mean field theories of ion distributions, such as the Gouy-Chapman theory that describes the distribution near a charged planar surface, ignore the molecular-scale structure in the liquid solution. The predictions of the Gouy-Chapman theory vary substantially from our x-ray reflectivity measurements of the interface between two electrolyte solutions. These structural measurements are described well by ion distributions predicted by a version of the Poisson-Boltzmann equation that explicitly includes a free energy profile for ion transfer across the interface when this profile is described by a simple analytic form or by a potential of mean force calculated from molecular dynamics simulations. These x-ray measurements from the liquid-liquid interface provide evidence for the importance of interfacial liquid structure in determining interfacial ion distributions.



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