In situ Vibrational Spectroscopy of Contact Adsorbed Thiocyanate on Silver Electrodes: Experiment and Theory

In-situ FT-IR vibrational spectra of thiocyanate ions absorbed on polycrystalline Ag electrodes as a function of electrode potential and electrolyte concentration are reported. Interpretation of the results are performed with the help of ab initio SCF calculations of the electronic structure and bonding of thiocyanate to small silver clusters. It was concluded that thiocyanate ion adsorbs with S- N-end down in the double layer region for potentials greater than -0.3V versus AgAgCl. At potentials close to the potential of zero charge thiocyanate ion is absorbed flat and cannot be detected by IR.