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Proceedings Paper

Photodesorption of ammonia from GaAs(100) and Cu(111))
Author(s): Karl-Heinz Bornscheuer; Winfried Nessler; Kurt W. Kolasinski; Tobias Hertel; Martin Wolf; Eckart Hasselbrink
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Paper Abstract

The laser-induced desorption of ammonia from GaAs(100)-(4X6) and Cu(111) has been studied using (2+1)-photon resonance-enhanced multiphoton ionization as a state specific probe. A surprisingly marked isotope effect (NH3/ND3) in the photodesorption cross section of ammonia from GaAs(100) had indicated that internal degrees of freedom play a crucial role in the desorption dynamics. We find that NH3 desorbs with a mean translational energy, (Etrans), of 300 K and 600 K for GaAs(100) and Cu(111), respectively. The average extent of vibrational excitation is about 1000 K. The rotational temperatures are 520 and 170 K. These results are interpreted in terms of a direct mechanism for NH3 desorption in which a reaction path which initially follows the internal v2 coordinate and then bends towards desorption is dominating. A marked unequal population of the inversion symmetry doublet states is observed.

Paper Details

Date Published: 25 September 1995
PDF: 9 pages
Proc. SPIE 2547, Laser Techniques for Surface Science II, (25 September 1995); doi: 10.1117/12.221474
Show Author Affiliations
Karl-Heinz Bornscheuer, Fritz-Haber-Institut der Max-Planck-Gesellschaft (Germany)
Winfried Nessler, Fritz-Haber-Institut der Max-Planck-Gesellschaft (Germany)
Kurt W. Kolasinski, Fritz-Haber-Institut der Max-Planck-Gesellschaft (Germany)
Tobias Hertel, Fritz-Haber-Institut der Max-Planck-Gesellschaft (Germany)
Martin Wolf, Fritz-Haber-Institut der Max-Planck-Gesellschaft (Germany)
Eckart Hasselbrink, Fritz-Haber-Institut der Max-Planck-Gesellschaft (Germany)


Published in SPIE Proceedings Vol. 2547:
Laser Techniques for Surface Science II
Janice M. Hicks; Wilson Ho; Hai-Lung Dai, Editor(s)

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