ELECTROCHEMICAL AND RAMAN-SPECTROSCOPIC STUDIES OF PYRAZINE ADSORPTION AT THE AU(210) ELECTRODE SURFACE

Chronocoulometry and Raman spectroscopy have been applied to study pyr azine adsorption at the Au(210) electrode surface. The adsorption isot herms, Gibbs energies of adsorption, and the electrosorption valency f or pyrazine adsorption at the Au(210) electrode surface have been dete rmined. Surface-enhanced Raman Scattering (SERS) spectra of pyrazine a dsorbed on an ''unroughened'' Au(210) electrode surface have been obta ined for the first time. The thermodynamic data and the SERS spectra i ndicate that pyrazine adsorbs on the Au(210) electrode via the nitroge n lone pair (N-bonded configuration) over the whole range of electrode potentials investigated. Consequently, the pyrazine molecule assumes only the vertical orientation at this surface of gold. The adsorption of pyrazine at the Au(210) and Au(111) surfaces is compared and the in fluence of the surface crystallography on the adsorption of this molec ule at gold electrodes is discussed.