This article reports the observation of large surface-enhanced Raman scattering (SERS) (106) for 4-tert-butylpyridine molecules adsorbed on a silver electrode surface in an electrochemical cell with electrode potential set at − 0.5 V.
A decrease in electrode potential to − 0.3 V was accompanied by a decrease in relative intensities of the vibrational modes; however, there were no changes in vibrational wavenumbers. Comparison of both normal solution Raman and SERS spectra showed very large enhancement of the intensities of a1, a2, and b2 modes at laser excitation of 488 nm. Enhancement of the non-totally symmetric modes indicates the presence of charge transfer as a contributor to the enhancement. (publisher abstract modified)