Regensburg 2002 – wissenschaftliches Programm
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O: Oberflächenphysik
O 22: Adsorption an Oberfl
ächen (II)
O 22.7: Vortrag
Dienstag, 12. März 2002, 17:45–18:00, H36
A DFT study of low coverage Br adsorption on the Pt(110)-(1×2) missing-row surface — •C. Franchini1, J. Redinger1, C. Deisl2, K. Swamy2, E. Bertel2, E.K. Vestergaard3, P. Thostrup3, E. Laegsgaard3, and F. Besenbacher3 — 1Center for Computational Materials Science, Vienna University of Technology, Vienna, Austria — 2Institute of Physical Chemistry, University Innsbruck, Innsbruck, Austria — 3Institute of Physics and Astronomy and CAMP, University of Aarhus, Aarhus, Denmark
The Pt(110) surface is known to reconstruct into a (1x2) structure of missing-row type (MR) with significant relaxations penetrating rather far into deeper layers. In this work we report on low coverage adsorption of Br on a Pt(110)-p(1x2) MR surface. STM experiments show that Br is mobile down to T ≈ 130 K. Using the Vienna Ab initio Simulation Package (VASP) and the Full-potential Linearized Augmented Plane Wave package FLAIR we studied the structural and electronic properties of the clean and Br-covered surface. Our investigation is mainly devoted to the search of favorable diffusion trajectories and barriers. In order to identify a diffusion mechanism explaining the mobility of bromine as found in the experiment, we have simulated molecular and atomic adsorption and diffusion pathways. We found Br to adsorb atomically on short bridge sites and to diffuse by normal ad-atom hopping. Under no conditions substitutional or subsurface adsorption is found.