Wavelength Dependence of Surface-Enhanced Raman Scattering from Ag Colloids with Adsorbed CN(-) Complexes, SO3(--), and Pyridine,
YALE UNIV NEW HAVEN CT
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Ag colloids with adsorbed CN- complexes, pyridine, and HSO3-SO32- ions are prepared and characterized by their elastic scattering spectra, extinction spectra, and particle size distributions. Enhanced Raman spectra from these colloids are measured as a function of incident laser wavelength over the 423-676.4-mn range. The maximum in the excitation profile for the Raman scattering shifted to a longer wavelength than that for the elastic scattering and extinction profiles. Furthermore, the Raman excitation profile peaked at a longer wavelength than that predicted by the electromagnetic calculations for the field at the tips of and surface-averaged over isolated spheres of various radii. The effect of colloid aggregation on the SERS intensity of CN- complexes adsorbed on the Ag colloids is discussed. Originator-supplied keywords include Wavelength Raman scattering Colloids Silver colloids.
- Atomic and Molecular Physics and Spectroscopy