Reflectance and ellipsometry of metal/electrolyte interfaces

Abstract

The improving sensitivity and increasing use of optical reflection techniques in the study of metals and semiconductors in contact with electrolytes, makes it timely to review the interpretation of such measurements. The surface charge on the conductor, the layer of solvent molecules forming the compact layer, the adsorption of ions on the electrode as well as the distribution of ions in the diffuse layer, are all features of the electrical double layer which can contribute to optical measurements. Models of these features are described which facilitate computation of their optical effects, and specimen results are presented. The fact that all of these features may make comparable contributions to optical measurements is illustrated for the system mercury + aqueous sodium fluoride, and the predicted contributions are compared with experimental results.