SURFACE-ENHANCED INFRARED ATR SPECTROSCOPY FOR IN-SITU STUDIES OF ELECTRODE-ELECTROLYTE INTERFACES

Infrared (IR) spectra of molecules adsorbed on a silver electrode surface have been investigated by using the Kretschmann attenuated-total-reflection (ATR) method, where a thin metal film evaporated on an ATR prism was used as the electrode. The sensitivity of this technique is ca. 50 times higher than that of reflection-absorption spectroscopy (RAS) technique due to a surface enhanced IR absorption phenomenon associated with surface roughness of the evaporated metal film. The advantage of the ATR spectroscopy is discussed in comparison with RAS. The mechanism of the surface-enhanced IR absorption phenomenon is also discussed theoretically.