Abstract
The process of electron stimulated desorption of adsorbates from metal surfaces is investigated within the framework of quantum mechanical scattering theory. The Born-Oppenheimer adiabatic approximation is assumed to be valid for the adsorbate motion. The transition amplitude for desorption via the resonant excitation of excited states of the adsorbate then can be factorized into an electronic excitation amplitude and a Franck-Condon factor. The Franck-Condon factor is more complicated than in molecules. The continuum of substrate excitations coupling to the adsorbate gives rise to an absorptive part of the Born-Oppenheimer potential governing the motion of the adsorbate in the excited state. This absorptive part leads to a considerable reduction of the desorption cross section. Explicit quantum mechanical expressions for the corresponding reduction factor are given.
The desorption of neutrals is considered in some detail. It turns out that within the adiabatic approximation this process requires the existence of neutral excited states of the adsorbate. The reneutralization of ionic excited states by electron capture from the substrate back into the ground state of the adsorbate, while possible on purely energetical grounds, occurs with zero probability in the adiabatic approximation and thus cannot be responsible for the large abundance of neutral desorbing particles. Neutral excited states of the adsorbate in principle should show up in inelastic electron scattering. The relation between electron stimulated desorption cross sections and inelastic electron scattering cross sections is discussed briefly.
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References
Menzel, D., Gomer, R.: J. Chem. Phys.41, 3311 (1964)
Redhead, P.A.: Canad. J. Phys.42, 886 (1964)
Menzel, D., Gomer, R.: J. Chem. Phys.41, 3329 (1964) Menzel, D.: Desorption Phenomena Topics in Applied Physics4, Berlin-Heidelberg-New York: Springer 1975
Tsukada, M., Brenig, W.: Z. Physik (to be published)
Brenig, W., Pabst, W.: (to be published)
Brenig, W., Schönhammer, K.: (to be published)
Born, M., Huang, K.: Dynamical Theory of Crystal Lattices, Appendix VII. Oxford: Oxford University Press 1956
Goldberger, M.L., Watson, K.M.: Collision Theory, Section 5. New York: Wiley and Sons 1964
Menzel, D.: Ber. Bunsenges., Phys. Chem.72, 591 (1968)
Pabst, W.: Dipl. Thesis, Physikdept. TUM, München (1973) (unpublished)
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On leave of absence from (present address) Physikdepartment der TUM, München-Garching and Max-Planck-Institut für Festkörperforschung, Stuttgart
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Brenig, W. Quantum theory of electron stimulated desorption. Z Physik B 23, 361–368 (1976). https://doi.org/10.1007/BF01316545
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DOI: https://doi.org/10.1007/BF01316545