ABSTRACT Structural transformations in the adsorption layer caused by an electric potential are investigated using the experimental data on the capacitance of a double electric layer for a gold electrode in molten sodium, potassium and cesium bromides. Comparing the double electric layer to a flat capacitor, the effective length of the electrode charge shielding and changes in the charge density depending on the applied potential are estimated. It is found that near the minimum potential of the capacitance curve, the shielding length decreases when the potential shifts towards positive values due to the deformation of the double layer. The deformation reaches critical values at the potentials of –0.025, –0.100 and –0.075 V for the Au|NaBr, Au|KBr and Au|CsBr systems, respectively, and decreases sharply at more positive potentials. The analysis of the dependence of the charge density on the electrode revealed the effect of shielding of potential-induced gold cations by salt phase anions. The strong Raman-active Au–Br stretching mode was observed at 210 cm–1 for the electrode surface after anode polarization. This can be explained by the transfer of anions across the interface resulting in the formation of ordered layers of ion associations on a positively charged surface.
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