Geochemical Equilibria and Reaction Dynamics: Atomic- to Pore-Scale Processes

Prof. Geiger and his research associates will adapt second harmonic generation (SHG) and vibrational sum frequency generation (SFG) investigate how the point of zero charge of quartz surfaces depends on the concentration and type of electrolyte used. They will also study the various surfaces of à192Ñ-quartz single crystals in contact with aqueous electrolyte solutions involving various ionic strengths (e.g. 0.1 microM to 0.5 M), pH values (e.g. 2 to 12), and metal cation (e.g. Ba2+ and Sr2+) concentrations. They will determine the differences in the electrostatic, thermodynamic, and structural parameters that distinguish fused silica surfaces from single crystal quartz surfaces, which are the targets for the related computational effort within the ORNL project ¡§Geochemical Equilibria and Reaction Dynamics (ERKCC72, Wesolowski, PI). Once this capability is implemented and tested for neat water/quartz interfaces, it will be used to explore the effects of solutes on interfacial species and the changes in the hydrogen bonding they produce.