Corrosion and Oxidation Studied by Valence Band Photoemission and X-Ray Diffraction

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This grant is in the general field of analytical and surface chemistry and the subfield of surface chemistry of metal corrosion and passivation. Professor Peter Sherwood will combine theoretical calculations of valence band density of states for estimations of spectral response with measurements of photoemission from core and valence levels to study the structure of oxide formation at polycrystalline metal surfaces and the structure of molecular species which inhibit corrosion. Unique facilities to combine x-ray diffraction with these measurements will allow in depth understanding of mechanisms of corrosion resistance. From these data, molecular design of such systems can be used for particular metal surfaces. X-alpha calculations of valence band density of states have been uniquely developed by Professor Sherwood for direct comparison to photoemission measurements. By using data from an in-situ electrochemical cell the entire process of passivation or corrosion can be followed. X-alpha calculations will be verified with other (e.g. ab initio) methods for simple systems and combined for direct comparison to photoemission measurements. Further verification of structure will be accomplished with thin film x-ray diffraction. The systems to be studied are active polycrystalline metals (iron, aluminum and nickel) in combination with specific organic corrosion inhibitors.