Interfacial structure of dimethylsulfoxide at Ag electrodes from surface enhanced Raman scattering and differential capacitance

Surface enhanced Raman scattering (SERS) and differential capacitance have been used to study interfacial structure in LiBr-containing dimethylsulfoxi de (DMSO) at Ag electrodes. The potential-dependent orientation of this sol vent is driven by interactions of the O atoms with the AE surface at positi ve potentials and by interactions of the S atoms with the surface at negati ve potentials. Significant spectral changes are observed at potentials in t he vicinity of the pzc indicating reorientation of interfacial solvent mole cules. Evidence for unique potential-dependent interactions of Li+ and Br- with DMSO and trace amounts of H2O in the electrochemical interface have be en uncovered on the basis of their spectral signatures. Potential-dependent molecular pictures of the interface in this system are proposed. (C) 1999 Elsevier Science S.A. All rights reserved.