Adsorbate Photochemical Dynamics

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This research project, supported in the Analytical and Surface Chemistry Program, addresses the question of the detailed dynamics of molecules photoexcited while adsorbed on transition metal surfaces. A nanosecond tunable pulsed laser system is used to initiate photodesorption, photofragmentation, and photoreaction of adsorbate molecules such as methane, nitrogen, and carbon monoxide adsorbed on the Pt(111) surface. Angle resolved time of flight mass spectrometry is used to examine species desorbing into the gas phase, and surface analytical tools are used to examine changes to the substrate. Electron mediated photoprocesses will be examined by the use of alkali adsorbates to lower the work function of the metallic substrate. Detailed information obtained in this research will be useful for our growing understanding of heterogeneous catalysis and photoassisted electronic materials processing. The interaction of light with adsorbed molecules forms the primary focus of this research project supported in the Analytical and Surface Chemistry Program. Laser initiated processes such as desorption, fragmentation, and reaction will be probed by examining the gas phase product of the process as well as changes to the metallic substrate. Insights into the operation of heterogeneous catalytic systems, as well as mechanistic information about laser assisted processing of electronic materials, should result from these studies.