Electrochemical Interfaces and Electrode Processes.

This report summarizes ONR research on the development and use of spectroscopic techniques for the study of electrochemical interfaces and electrode processes occurring at such interfaces. A number of in-situ techniques have been used including ultraviolet-visible reflectance spectroscopy and ellipsometry, infrared attenuated total reflectance spectroscopy, surface enhanced and resonant Raman spectroscopy, and Mossbauer spectroscopy. These in-situ techniques have provided important insight into the electronics and the properties of adsorbed molecules, ions and atoms at electrochemical interfaces. They have also been used to examine the adsorption isotherms and kinetics of adsorption-desorption. The in-situ techniques, however, are insufficient to establish the type of adsorption sites or compositional questions. For this reason substantial use has also been made of ex-situ surface physics techniques including LEED, AES, XPS and secondary ion mass spectroscopy. Special hardware and techniques have been developed as part of the ONR contract research to facilitate the transfer of electrodes between the electrochemical and ultrahigh vacuum environments and vice versa with the possibility for restructuring and contamination at a minimum. The report describes the application of these techniques to adsorption on single crystal electrodes. Author