The Raman scattering of several azo dyes coadsorbed with pyridine on silver sols is investigated, and their surface spectra and excitation behavior are reported. It is found that the scattering of pyridine is enhanced by a factor of >105, while that of the dyes is enhanced to a much smaller degree. This effect is most pronounced for dyes that in solution are in resonance with the incident light, in which case the enhancement is many orders of magnitude smaller than for coadsorbed pyridine. Using a "chemical" detuning experiment, it is shown that the enhancement factors of the dyes gradually increase for molecules which are progressively out of resonance.
ASJC Scopus subject areas
- Engineering (all)
- Physical and Theoretical Chemistry