Combined Surface-Enhanced and Resonance-Raman Scattering from the Aspartic Acid Derivative of Methyl Orange on Colloidal Silver

Article abstract of DOI:10.1021/j150644a004

By selecting a chromophore, dabsyl (N-4-dimethylaminoazobenzene-4'-sulfonyl) aspartate (DABS-ASP), whose absorption spectrum overlaps with the surface-enhanced Raman scattering (SERS) excitation profile for colloidal silver sols, we have found it possible to study the triple combination of resonant Raman scattering (RRS) of the DABS-ASP in solution and both the combined RRS-SERS (SERRS) and the SERS of DABS-ASP adsorbed on the colloidal silver particles.The SERRS and SERS spectra were distinctly different from each other.The measured surface enhancements were in excess of 10³.This is less than the values of the order of 10⁵ measured earlier for citrate on these silver sols.Just as for citrate, the excitation profiles peaked at about 500 nm whereas the main absorption band was in the region of 400 nm, a disparity from our electrodynamic model for SERS.