Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 26: Oxides and insulators: Clean surfaces
O 26.3: Vortrag
Dienstag, 23. März 2010, 11:00–11:15, H40
Interaction potential for fast atoms in front of KCl(001) surface — •Uwe Specht1, Marco Busch1, Konrad Gärtner2, and Helmut Winter1 — 1Humboldt-Universität zu Berlin, Institut für Physik, Newtonstraße 15, D-12489 Berlin, Germany — 2Friedrich-Schiller-Universität Jena, Institut für Festkörperphysik, Max-Wien-Platz 1, D-07743 Jena, Germany
Fast He, Ne, Ar and N atoms with energies from 1 kev up to 60 keV are scattered under grazing angles of incidence (≤2∘) from a clean and flat KCl(001) surface. For scattering along low-index directions (axial surface channeling), we observe pronounced peaks in the angular distribution of the scattered projectiles. This can be attributed to rainbow-scattering caused by the corrugated interaction potential. On the basis of classical trajectory calculations, we derive from comparison with the experimental data the effective interaction potential of He, Ne, Ar and N atoms in front of a KCl(001) surface. Fair agreement is found for individual pair potentials calculated from Hartree-Fock wave functions, where the charge state of K and Cl ions located at lattice sites of the ionic crystal is taken into account. For the generalized ZBL (Ziegler, Biersack and Littmark) and OCB (O’Connor and Biersack) potentials, the agreement for interaction energies below 20 eV is found to be poor.