Surface-enhanced Raman scattering by citrate on colloidal silver

Abstract

Surface-enhanced Raman scattering (SERS) spectra have been obtained for citrate adsorbed on Carey-Lea sols of various particle sizes and degrees of aggregation. Analysis of adsorbed citrate by a radioactive exchange technique has permitted determination of absolute enhancements. Maximum measured enhancements of 2 × 105-4 × 105 agreed with electrodynamic calculations for the particle size histograms determined by electron microscopy. However, a discrepancy between the sharp maxima in the absorption spectra as well as in the calculated SERS excitation profiles near 400 nm and the broad maxima in the measured SERS excitation profiles near 500 nm remains unresolved. © 1983 American Chemical Society.