Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 14: Adsorption on semiconductors, oxides and insulators II
O 14.6: Vortrag
Montag, 26. März 2012, 17:15–17:30, MA 041
LEED I(V) analysis of oxygen physisorption on the rumpled NaCl(100) surface — Anne Möller, Stephan Härtel, •Jochen Vogt, and Helmut Weiss — Chemisches Institut der Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany
Among the diatomic molecules, O2 is unique due to
its magnetic properties in the gas phase and in the bulk[1]. The
structure of O2 adsorbed on the NaCl(100) surface is of interest
in many respects, e. g. for studies of the surface aligned
photochemistry of O2. We have characterized the physisorption of
O2 using low-energy electron diffraction (LEED) with primary
electron currents in the nA range and electron energies above 70 eV.
No signs of electron beam induced charging of the NaCl surface were
perceptible even at cryogenic temperatures. A saturated 2D phase
O2-p(1×1)/NaCl(100) was prepared at temperatures below 31
K. LEED diffraction spot intensities were recorded as a function of
electron energy. The subsequent determination of the adsorbate
structure based on a full-dynamical LEED-I(V) analysis reveals that
O2 is bound on top of the Na+ cations. The rumpling of the
NaCl(100) surface [2] appears to be unaffected by the adsorbed O2,
consistent with its very weak interaction with
the substrate. The details of the adsorbate structure will be
discussed and
compared with the results of model calculations.
Y. A. Freiman, H. J. Jodl, Phys. Rep. 401 (2004), 1
J. Vogt, H. Weiss, Surf. Sci. 491 (2001), 155