SURFACE-ENHANCED RAMAN-SCATTERING FROM FERROCYANIDE AND FERRICYANIDE IONS ADSORBED ON SILVER AND COPPER COLLOIDS

Surface-enhanced Raman scattering has been observed from the adsorptio n of ferrocyanide (hexacyanoferrate(II)) and ferricyanide (hexacyanofe rrate(III)) ions on Ag and Cu colloids and electrodes. Both ferrocyani de and ferricyanide ions interact strongly with Ag and Cu surfaces, an d are bonded to surfaces via the end-on bridging CN sigma-bondings. Ch emisorption lowers site symmetry of the adsorbed states, resulting in the activation of Raman forbidden modes in the low-frequency as well a s the nitrile-stretching regions. (C) 1998 Elsevier Science B.V. All r ights reserved.