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

Infrared (IR) spectra of molecules adsorbed on a silver electrode surf ace have been investigated by using the Kretschmann attenuated-total-r eflection (ATR) method, where a thin metal film evaporated on an ATR p rism was used as the electrode. The sensitivity of this technique is c a. 50 times higher than that of reflection-absorption spectroscopy (RA S) technique due to a surface enhanced IR absorption phenomenon associ ated with surface roughness of the evaporated metal film. The advantag e of the ATR spectroscopy is discussed in comparison with RAS. The mec hanism of the surface-enhanced IR absorption phenomenon is also discus sed theoretically.