SERS Mechanism of Adsorbed Molecules on Ag₂O Colloids

In order to understand the SERS （Surface-enhanced Raman Scattering） mechanism of adsorbed molecules on Ag₂O,the in fluences of Na₂S₂O₃ and NaOH on the SERS and the time dependence of the SERS of the adsorbed molecule D266 on Ag₂O colloids were studied respectively.The results indicate that chemical enhancement is dominant.The complexes of adsorbed molecules and small silver ion cluster（such as Ag₄+）on Ag₂O constitute SERS activesites.At the sites,charge transfer between adsorbed molecules and small silver ion clusters is the main enhanement origin.The enhancement factor is theoretically estimated with the excited-state charge transfer model,which is in accordance with the experiments.