Time-Resolved EUV-Probed Surface Chemistry

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Professor Margaret Murnane of the University of Colorado is funded by the Analytical and Surface Chemistry Program to study femtosecond dynamics of well-characterized adsorbate/surface systems using extreme ultraviolet (EUV) and x-ray radiation. New shorter wavelengths of light produced through high harmonic generation will be utilized to access adsorbate core levels. In particular, charge transfer dynamics will be studied when oxygen on single crystal platinum (111) is subjected to laser pulses five femtoseconds in length. Also, the oxidation of CO on this same crystal face is to be examined. The ability to measure dynamics of a surface reactant as it evolves between different equilibrium states by photoemission has been very restricted, because ultrafast x-ray sources with sufficient flux and short pulse duration have not been available until very recently. The femtosecond and picosecond timescales are appropriate to the basic atomic motions underlying surface reactions.The work will increase our understanding of charge transfer processes on surfaces. Charge transfer is a chemical phenomenon underlying diverse processes such as electrochemistry and biochemistry. The area of femtochemistry was recently recognized as a frontier by the Nobel Prize in Chemistry in 1999.