Water/pyridine/gold system

The increase in frequency in the pyridine/water/gold system was associated in Ref. 98 with the effect of adsorption on the structure of the solvent at the interface. Adsorbed pyridine molecules destroy the structure of water and replace the water-water interactions between the first layer and further layers at the interface, by pyridine-water interactions, which must be much weaker. Such a replacement becomes more effective, as the coverage by pyridine increases. The same explanation was found to be applicable for the adsorption of n-butanol and t-butanol on gold from aqueous solutions, as shown in Fig. 9c and d. 

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