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Project Progress

Using reaction path modeling we have been able to place important constraints on the formation of secondary minerals often viewed as having catalytic potential. The results of the work indicate that the composition of the secondary mineral assemblage is predominantly controlled by the degree mass transfer with the atmosphere is allowed. Weathering reactions proceeding with unimpeded transfer between the hydrosphere and atmosphere leads to a mineral assemblage dominated by simple binary minerals. By contrast, when weathering reactions proceed without exchange with the atmosphere, complex secondary minerals, such as zeolites are formed. In addition, these restricted environments become very reducing and alkaline—conditions favorable for the stabilization of metal alloys. These results indicate that systems with restricted exchange with the atmosphere (e.g., cracks in the ocean floor) may have more catalytic potential than systems open to the atmosphere.

In this year we have started to use a molecular modeling package (Gaussian 03) to evaluate the energetics and kinetics of Fe(II) mediated reduction of dinitrogen and the photochemical reduction of dintrogen with Fe(II) as the electron donor. The results of these calculations, in collaboration with Dr. James Kubicki at Penn State, have guided the design of experiments that are now underway. Integration of theoretical and experimental studies is an important step in more efficiently studying the vast array of reactions that are of interest to researchers in the field of prebiotic chemistry.