This award provides 60% funding for the acquisition of a combined atomic force and scanning tunneling microscope system that will be installed and operated in the Beckman Institute Materials Resource Center at the California Institute of Technology. Funding from the National Science Foundation will be shared equally between the divisions of Chemistry and Earth Sciences. Caltech is committed to providing the remaining 40% funding required. The microscope system will be capable of imaging surface topography of materials at the resolution of individual atoms. It will be applied in a large number of research projects at Caltech where surface analysis is critical; for example the interaction of aqueous species at solid-liquid interfaces.