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Surface-enhanced Raman scattering (SERS) by molecules adsorbed at spherical particles: errata

Journal Article · · Appl. Opt.; (United States)
DOI:https://doi.org/10.1364/AO.19.004159· OSTI ID:5760048

A model for Raman scattering by a molecule adsorbed at the surface of a spherical particle is articulated by treating the molecule as a classical electric dipole. This follows Moskovits's suggestion (J. Chem. Phys. 69, 4159 (1978)) and the experiments by Creighton et al. (J. Chem. Soc. Faraday Trans. II, 75, 790(1979)) that such a system may exhibit SERS simlar to that at roughened electrode surfaces. The molecule is stimulated by a primary field comprised of the incident and near-scattered fields. Emission consists of the dipole field plus a scattered field, each at the shifted frequency. Addition of feedback terms between the dipole and the particle makes only a negligible contribution to the fields. For pyridine adsorbed at the surface of a silver sphere, the 1010 cm/sup -1/ band is enhanced by approx.10/sup 6/ if the radius is much less than the wavelengths and the excitation wavelength is approx.382 nm, a wavelength for which the relative refractive index of silver is close to m = ..sqrt..2i. Detailed results are given for the effect upon the angular distribution and the polarization of the Raman emission of particle size, distance from the surface, excitation wavelength, and location of the molecule upon the surface. These results simulate those observed at roughened silver electrodes and suggest that the mechanism of SERS at those electrodes may resemble the electromagnetic mechanism elucidated here. The authors predict that comparable effects should be observed for fluorescent scattering. 53 references, 9 figures.

Research Organization:
Clarkson Coll. of Tech., Potsdam, NY
OSTI ID:
5760048
Journal Information:
Appl. Opt.; (United States), Journal Name: Appl. Opt.; (United States) Vol. 19:24; ISSN APOPA
Country of Publication:
United States
Language:
English