SPECTROSCOPIC TECHNIQUES FOR THE STUDY OF SOLID-LIQUID INTERFACES.

Substantial progress has been made with in-situ use of optical reflectance spectroscopy and Raman spectroscopy in studies of the properties of solid-liquid interfaces and particularly metal- and semiconductor-electrolyte interfaces. Such techniques provide molecular level information concerning adsorbed species and various thin films not available from electrochemical and other measurements. Ex-situ techniques including electron and ion spectroscopies also have proved helpful in understanding the properties of solid-liquid interfaces but special techniques are necessary to minimize changes in the surface structure of the solid during the transfer between the liquid and ultrahigh vacuum environment. Some of the results obtained recently by various workers using such transfer techniques in the study of adsorption on single crystals at electrochemical interfaces are reviewed. For adsorption on some solid surfaces there is parallel behavior in the liquid and vacuum environments and comparison affords insight as to the interactions of the adsorbed species at solid-liquid interfaces.