State-Resolved Dynamics of Gas-Surface Reactions

Tufts University, Medford MA

Investigators

Abstract

Dr. Arthur L. Utz of Tufts University is funded for his research on state-resolved dynamics of gas-surface reactions by the Physical Chemistry Program of the Chemistry Division. The gas-surface reaction dynamics of model reaction systems will be studied to test theoretical predictions and establish mechanistic insights into hetergeneous chemistry. Four specific areas will be examined: (1) Vibrational mode specificity in gas-surface reactivity will be examined because statistical models are inadequate. Molecular dissociation on Ni(100) (e.g., of methane) will be examined to find mode-specific dissociation probabliities in reagents and to establish predictively-useful trends. (2) Orientation, reorientation and stereochemical effects will be studied by using polarized laser light to anisotropically excite the reagent molecules. (3) Trapping-mediated reaction channels for internally excited molecules will be used to examine how internally excited molecules reactively encounter surfaces in molecular beam reflectivity experiments. (4) Bond-selective chemistry will focus on the examination of methane, trideutero-methane, and HOD dissociation on Ni(100) and the influence of vibrational mode excitation on the reaction products. Heterogeneous chemistry has a tremendous economic and technological impact in the chemical industry. The gas-surface reaction studies at Tufts University will provide means for improving our understanding of the mechanistic role of internal vibrations and internal energy on gas-surface reactions. Such reactions are commonly encountered in bulk chemical production, in pollution control devices, etc. Lasers will be used to selectively excite such internal vibrations, and their utility in controlling reaction chemistries will be extended.