Surface-enhanced infrared absorption spectrometry of p-nitrothiophenol andits disulfide

The surface-enhanced infrared spectrometry of p-nitrothiophenol and its dis ulfide on silver films has been investigated by using deposition from solut ion, from self-assembled monolayers, and from the vapor phase using a direc t-deposition gas chromatography/infrared (GC-IR) interface. In solution, th e thiophenol oxidizes to form the disulfide, which then adsorbs to the silv er film. If a silver film is deposited on top of a layer of the disulfide, the resulting spectrum is strongly different from that seen with a silver u nderlayer, more closely resembling the spectrum obtained from the self-asse mbled monolayer. When a GC-IR interface is used, the presence of the enhanc ement appears to he correlated with temperature-dependent chemisorption.