Anion-induced charge-transfer enhancement in SERS and SERRS spectra of Rhodamine 6G on a silver electrode: how important is it?
✍ Scribed by W. Grochala; A. Kudelski; J. Bukowska
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 217 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0377-0486
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✦ Synopsis
An additional anion-induced enhancement of surface-enhanced Raman scattering (SERS) and surface-enhanced resonance Raman scattering (SERRS) for Rhodamine 6G adsorbed on a silver electrode upon addition of chloride and citrate anions was determined as a function of the applied potential. The observed increase in intensities amounts to about 100-and 10-fold, for SERS and SERRS spectra, respectively. It was shown that the total increase in SERS intensity by added anions cannot be exclusively explained in terms of the potential-dependent charge-transfer e †ect and by the "active sitesÏ e †ect caused by thermodynamically unstable atomic-scale roughnesses. We suggest that this increase can be also ascribed to anion-induced reorientation of the dye molecule or to the potential-independent molecular resonance caused by the strong inÑuence of coadsorbed chloride ions on the electronic levels of Rhodamine 6G.