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Title: Characterization of Lewis acid sites on the (100) surface of {beta}-AlF{sub 3}: Ab initio calculations of NH{sub 3} adsorption

Journal Article · · Journal of Chemical Physics
DOI:https://doi.org/10.1063/1.2933523· OSTI ID:21104061
; ;  [1];  [2];  [1]
  1. Computational Science and Engineering Department, STFC Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD (United Kingdom)
  2. Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)

The current study employs hybrid-exchange density functional theory to show that the Lewis base, NH{sub 3}, binds to the {beta}-AlF{sub 3} (100) surface with a binding energy (BE) of up to -1.96 eV per molecule. This is characteristic of a strong Lewis acid. The binding of NH{sub 3} to the surface is predominately due to electrostatic interactions. There is only a small charge transfer from the NH{sub 3} molecule to the surface. The BE as a function of coverage is computed and used to develop a lattice Monte Carlo model which is used to predict the temperature programed desorption (TPD) spectrum. Comparison with experimental TPD studies of NH{sub 3} from {beta}-AlF{sub 3} strongly suggests that these structural models and binding mechanisms are good approximations to those that occur on real AlF{sub 3} surfaces.

OSTI ID:
21104061
Journal Information:
Journal of Chemical Physics, Vol. 128, Issue 22; Other Information: DOI: 10.1063/1.2933523; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
Country of Publication:
United States
Language:
English