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Proceedings Paper

Multidimensional dynamics in surface reactions
Author(s): Xiao-Yang Zhu
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Paper Abstract

The conceptual starting point in surface dynamics is the potential energy surface, the most celebrated of which is the one proposed by Lennard-Jones 65 years ago. The Lennard- Jones potential considers two adsorption states as a molecule approaches the surface: a molecular precursor state and a chemisorption state. While this simple model has contributed much to the development of surface reaction dynamics, its one-dimensionality is of significant limitation. Molecule-surface interactions are inherently multidimensional. For example, molecular internal motions, substrate motions, and the relative orientations of a molecule to surface atoms are all important in determining the chemical consequence of a surface process. These issues are illustrated using recent examples involving polyatomic species. In the first example, electronic excitation/de-excitation of adsorbed NH3 results in internal vibrational excitation, which can couple efficiently to the adsorbate-surface coordinate and results in desorption. In the second example, the thermal desorption of CH3 from GaAs can lead to vibrational excitation in the product. The third example shows that a substantial amount of energy released by adsorbate-surface bond formation can be transferred to the intramolecular modes, leading to the ejection of energetic products.

Paper Details

Date Published: 30 April 1998
PDF: 7 pages
Proc. SPIE 3272, Laser Techniques for Surface Science III, (30 April 1998); doi: 10.1117/12.307142
Show Author Affiliations
Xiao-Yang Zhu, Univ. of Minnesota/Twin Cities (United States)

Published in SPIE Proceedings Vol. 3272:
Laser Techniques for Surface Science III
Hai-Lung Dai; Hans-Joachim Freund, Editor(s)

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