Charge-transfer enhancement in infrared absorption of thiocyanate ions adsorbed on a gold electrode in the Kretschmann ATR configuration

The intensity of an enhanced infrared absorption of SCN^- ions adsorbed on an Au film electrode reaches a maximum at a negative electrode potential, where the number of adsorbed ions should be smaller than at higher potentials. In addition, the enhancement of infrared absorption is restricted to species adsorbed directly on the electrode surface. These observations suggest that a charge-transfer enhancement is working on the infrared absorption of the SCN^-/Au electrode system. A probable precursor of the thiocyanato complex of Au was detected in the same system.