Circularly polarized component in surface-enhanced Raman spectra

Surface-enhanced Raman scattering (SERS) and Raman optical activity (ROA) spectra have been recorded for l-phenyloalanine and l/d-cysteine adsorbed on silver. For silver electrodes immersed in phenyloalanine solution ROA signals were strong, irreproducible, and probably due to products of phenyloalanine carbonization. For cysteine on silver electrode the ‘carbon peaks’ were weaker, surface ROA spectra were different than the bulk solution ones, and in broad wavenumber region surface ROA spectra for l- and d-cysteine were mirror images of each other. This suggests observation of surface-enhanced ROA (SEROA) effect. Circularly polarized components were significantly weaker in spectra measured on sols.