Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 67: Symposium: The Solid-Liquid Interface: A Challenge for Theoreticians II
O 67.5: Vortrag
Freitag, 30. März 2007, 11:45–12:00, H38
Theoretical study of the dynamics of gold islands on Au(100) — •Kay Pötting1, Paola Quaino1, Wolfgang Schmickler1, and Timo Jacob2 — 1Institut für Theoretische Chemie, Universität Ulm, 89069 Ulm, Germany — 2Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin-Dahlem, Germany
Nanostructures on metal electrodes are presently the subject of intensive investigations because they are expected to play an important role in future nanotechnologies. Their stability and dynamics has been found to depend exponentially on the electrode potential, an effect which we ascribe to the interaction of local dipole moments with the electric field of the double layer. In order to verify the validity of this conjecture, and to clarify the details of the underlying mechanism, we have investigated the dynamics of gold island on Au(100), which has been the subject of intense experimental investigations, by a combination of DFT calculations and kinetic Monte Carlo simulations. For this purpose, we have calculated the diffusion barriers and associated dipole moments for several important elementary processes by DFT. These results were combined with embedded atom potentials in order to generate the rates for all possible steps, which were then used as the basis for kinetic Monte Carlo simulations. In this way we have investigated both the dynamics of single islands and the Ostwald ripening of two islands of different sizes. Preliminary results indicate a strong effect of the field on energetic parameters like the step line tension and the kink energy, and on the rate of particle exchange and Ostwald ripening.