Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 60: Poster Session IV (Solid/liquid interfaces; Semiconductors; Oxides and insulators; Graphene; Plasmonics and nanooptics; Electronic Structure; Surface chemical reactions; Heterogeneous catalysis)
O 60.26: Poster
Mittwoch, 16. März 2011, 17:30–21:00, P4
LEED I(V) analysis of CO and N2 physisorption on the NaCl(100) surface — •Jochen Vogt and Helmut Weiss — Chemisches Institut der Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany
Carbon monoxide and N2 physisorbed on the NaCl(100) surface have
been considered in the past as model systems for orientational
order-disorder phase transitions in two dimensions [1,2]. Although
CO and N2 are isoelectronic, the lateral intermolecular potential
of adsorbed CO is governed by dipole-dipole interaction, while in
the case of N2 quadrupole-quadrupole interaction is the leading
electrostatic term. Low-energy electron diffraction experiments (LEED)
prove, that upon cooling below 35 K the lattice symmetry in the
system CO/NaCl(100) changes from a (1×1) to a (2×1).
However, few is known about the adsorbate structure from an
experimental point of view. We report a LEED I(V) structure analysis
of CO/NaCl(100) and N2/NaCl(100), guided by density functional
theory (DFT-D/PBE) calculations. Although predicted by theory [2],
our experiments do not support a disorder/order phase transition
(1×1)→(2×1) for N2/NaCl(100) above 18
K.
W. Rzysko, A. Patrykiejew, K. Binder, Phys. Rev. B 76 (2007), 195409
A. K. Sallabi, D. Jack, Phys. Rev. B 62 (2000), 4841