The magnitude of the plasma-resonance contribution to surface-enhanced Raman scattering on silver-island films has been measured with use of an experimental arrangement in which the resonance can be suppressed. The measured reduction in Raman scattering is ∼ 300, but theoretical analysis indicates that there may remain an additional unsuppressed factor ≲3. The data show that plasma resonances are not essential for observation of Raman scattering by molecular monolayers using standard detection techniques.

• Received 23 May 1983

DOI:https://doi.org/10.1103/PhysRevLett.51.593