| Autor: |
Barclay, V. J., Polanyi, J. C., Zeiri, Y., Kosloff, R. |
| Předmět: |
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| Zdroj: |
Journal of Chemical Physics; 6/1/1993, Vol. 98 Issue 11, p9185, 14p |
| Abstrakt: |
A quantum mechanical probe of surface and adsorbed layer structure is presented based on the photodissociation of ordered hydrogen halide adsorbates. The photolysis of the adsorbate molecule released atomic hydrogen which scattered from the surface as well as from neighboring adsorbed molecules. The coherent character of the hydrogenic wave function formed in the photodissociation process proved to be a revealing probe of the surface and of nearby adsorbates by way of localized atomic scattering (LAS). The dynamics of the H-atom motion were modeled by the time-dependent Schrödinger equation. This study includes two-dimensional simulations of the photodissociation of a single HBr molecule adsorbed on LiF(001) as well as photodissociation in full mono-layer and bilayer systems. It was found that for photolysis of an isolated adsorbate molecule, depending on the separation of the adsorbate from the surface, the angular distribution showed either a single specular peak (small z) or diffraction (larger z), while for higher coverage a series of diffraction peaks as well as peaks which corresponded to trapped unstable periodic orbits were observed. The quantization rules of these periodic orbits were identified and served as a link between the observed angular distribution and the structure of the adsorbed layer(s). [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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