ELECTRIC DOUBLE-LAYER STRUCTURE IN A SURFACE-INACTIVE ELECTROLYTE SOLUTION - EFFECT OF THE STERN LAYER AND SPATIAL CORRELATIONS OF SOLVENT POLARIZATIONстатья
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Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:The potential and ionic concentration distributions in the solution surface layer have been analysed at potentials near pzc. As with the Stern-Grahame approach, account is taken of the difference of the planes of closest approach for the solvent and ions to the electrode surface. Unlike the Gouy-Chapman theory, we incorporate an effect of the solvent structure resulting in the non-locality of its dielectric response to the external electric field. Our model predicts the Grahame equation for the capacitance of the system to be valid in sufficiently diluted solutions, whereas with increasing electrolyte concentration a deviation may generally take place, its sign depending on the ratio of the Stern layer thickness and the correlation length of the solvent polarization. For an aqueous 1:1 electrolyte solution it is concluded that a marked increase of "the compact layer capacity" is expected only at concentrations c approximately 1 M, in agreement with experimental data. At the same time the ionic charge distributions within the diffuse layer deviate drastically from the Gouy-Chapman one at much lower concentrations, remaining essentially smeared out in the normal direction even in rather concentrated solutions due to the non-locality of the solvent response.