Gold surfaces frequency shift

FIG. 8. Frequency shift versus surface charge density on gold and silver electrodes in 0.1 M solution of LiC104 in water (a) and in butanol (b). (Fig. 8a from Ref 98.)... 

FTIR spectroscopy was used for the analysis of ultrathin organic films on metals. FTIR in the reflection mode (IRRAS) was used to study the interaction of ultrathin films of dicyandiamide (hardener of most one-pack epoxy resins) with various substrates, model ones such as gold or zinc and industrial ones such as steel and zinc-coated steels. Pure zinc surfaces and, to a lesser extent, zinc-coated steels are shown to react with dicyandiamide after heating at 180 C, as evidenced by the frequency shift of the absorption band characteristic for nitrile groups. Some mechanically tested specimens are then analysed, after failure, by FTIR microspectrometry. The spectra obtained, corresponding to the fracture initiation zone which is about 100 micrometers in diameter, indicate the presence of an ultrathin layer of modified polymer still covering the substrate. 28 refs. 

FIGURE 6.33 Changes in frequency shift, Af due to adsorption of Fgi (curves 1, 3, 5, and 7) (and then HSA ) and HSA, (curves 2,4, 6, and 8) (and then Fg ) onto surfaces of (curves 1 and 2) gold, (curves 3 and 4) DLC, (curves 5 and 6) Ti, and (curves 7 and 8) TiN X is the relaxation time on HSA adsorption on Fg-coated surfaces. (Adapted from Gun ko, V.M., Mikhalovska, L.I., Tomlins, P.E., and Mikhalovsky, S.V., Competitive adsorption of macromolecules and real-time dynamics of Vroman-like effects, Phys. Chem. Chem. Phys., 13, 4476-4485, 2011b, Copyright 2011, with permission from The Royal Society of Chemistry.)... 

A similar situation is encountered when pyridine is adsorbed on gold from its solution in -butanol. The shift in frequency does not exceed 1.5 Hz. Butanol itself is oriented on the gold surface with its alkyl chain toward the solution. Pyridine adsorption does not seem to cause significant changes in the interaction of the vibrating surface with the liquid. 

FIG. 11. The frequency shift versus the surface charge density on gold electrode in 0.1 M LiC104 without (closed circles) and with (open circles) uracil (4 mM). 

Qualitatively similar delays of the frequency shift were observed [159] for the deposition of cobalt, nickel, and iron on the gold surface in all three cases the frequency is practically constant until a few atomic layers of metal have been deposited on the gold surface. Deposition of these metals is... 

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