Slow Fluctuations in Enhanced Raman Scattering and Surface Roughness Relaxation

D. B. Lukatsky, G. Haran, S. A. Safran

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


We propose an explanation for the recently measured slow fluctuations and “blinking” in the surface-enhanced Raman scattering spectrum of single molecules adsorbed on a silver colloidal particle. We suggest that these fluctuations may be related to the dynamic relaxation of the surface roughness on the nanometer scale and show that there are two classes of roughness with qualitatively different dynamics. The predictions agree with the measurements of surface roughness relaxation. Using a theoretical model for the kinetics of surface roughness relaxation in the presence of charges and optical electrical fields, we predict that the high-frequency electromagnetic field increases both the effective surface tension and the surface diffusion constant and thus accelerates the surface smoothing kinetics and time scale of the Raman fluctuations in a manner that is linear with the laser power intensity, while the addition of salt retards the surface relaxation kinetics and increases the time scale of the fluctuations. These predictions are in qualitative agreement with the Raman experiments.

Original languageEnglish
Article number062402
Number of pages4
JournalPhysical Review E
Issue number6
StatePublished - 1 Jun 2003
Externally publishedYes

ASJC Scopus subject areas

  • Statistical and Nonlinear Physics
  • Statistics and Probability
  • Condensed Matter Physics


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