Study of electrochemical interfaces by transient reflecting gratings

Picosecond photothermal/photoacoustic measurement of gold interfaces in some aqueous solutions of electrolytes was carried out using a transient reflecting grating (TRG) method. As the electric potential became more anodic, the TRG-induced diffracted-light intensity increased above that expected from the reflectivity change, and the transient waveform also changed, both in the electrical double-layer and Faradaic oxidation regions. These changes were related to the anions in the supporting electrolyte. These results are discussed with respect to the photothermal and photoacoustic effects at the nanometer-scale interface.