Adsorption of dimethyl sulfide and methanethiolate on Ag and Au surfaces: Surface-enhanced Raman scattering and density functional theory calculation study

Adsorption behaviors of dimethyl sulfide (DMS) and methanethiolate (MT) on chemically reduced Ag and Au colloidal nanoparticle surfaces have been comparatively examined to check its binding mechanism by means of surface-enhanced Raman scattering (SERS). The difference in adsorption strength between DMS and MT appeared to be greater on Ag than on Au. Irradiations at shorter wavelengths of 514.5 and 355 nm were employed to examine a photo-induced cleavage of DMS on the surfaces. Upon an irradiation at 355 nm, DMS could be detached on Ag, whereas such a photo-induced reaction would not occur on Au even for a higher amount of energy. A density functional theory (DFT) calculation was used for a better explanation of the dissimilar adsorption behaviors of DMS and MT on Ag and Au surfaces. (c) 2006 Elsevier B.V. All rights reserved.