CHEMICAL EFFECT OF CHLORIDE-IONS ON SERS IN SILVER SOL

The influence of chloride ions on surface enhanced Raman scattering (SERS) and the time dependence of the SERS intensity of p-aminobenzoic acid (PABA) and pyridine in silver sol were studied. The addition of chloride ions can destroy the equilibrium between the gas-like and the solid-like phase adsorption of PABA on the silver surface and causes a transformation of the molecular adsorption state and a reduction in the SERS intensity. The influence of chloride ions on SERS and the time dependence of SERS intensity in PABA-silver sol and pyridine-silver sol mixtures were studied. It was found that, in the same environment, the SERS' intensity of pyridine increases and that of PABA decreases on addition of KCl. The results show that the chemical effect of chloride ions on SERS of PABA and pyridine in silver sol is overwhelming. The results of light absorption of PABA and pyridine in silver sol are consistent with this conclusion.