Nonlinear Optical Surface Studies of Iron and its Oxides

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With this award, the Chemical Structure, Dynamics and Mechanisms (CSDM-A) Program of the Division of Chemistry is funding Professor Franz Geiger of Northwestern University to prepare and study films of iron and its oxides that are 100,000 times thinner than a sheet of paper. This approach makes it possible to literally shine light on important technological problems connected to iron, such as corrosion and environmental cleanup. By directly and indirectly interacting with students, teachers, lawyers, and policy makers, the Geiger group is also communicating science to the general public, specifically in the context of the Village of DePue, a superfund site located in the state of Illinois.Iron and its oxides are dark and heat up upon light exposure. Therefore, it is difficult to study their surfaces with instruments that use light, such as a microscope or a laser, and the understanding of many technological applications involving the surfaces of iron and its oxides remains limited. The project invokes a concept that dates back to 1729, when it became clear that diluting colored solutions allowed increasing amounts of light to pass through them. Applying this concept to iron solids, the Geiger group researchers will prepare and characterize nanometer-thin films of iron and its oxides and study their dynamically changing chemical and structural responses upon contact with technologically relevant fluids using a variety of interface-specific laser methods. Special attention will be paid to determining mechanisms of surface passivation so as to develop methods for rejuvenating iron substrates that otherwise deactivate over time.