Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 67: Symposium: The Solid-Liquid Interface: A Challenge for Theoreticians II
O 67.6: Vortrag
Freitag, 30. März 2007, 12:00–12:15, H38
DFT-Studies on the Potential-Induced Lifting of the Au(100) Surface Reconstruction — •Sudha Venkatachalam, Timo Jacob, and Matthias Scheffler — Fritz-Haber-Institut der MPG, D-14195 Berlin, Germany
The study of potential-induced changes of single crystal surface morphologies is of great interest because of its diverse application in electrocatalysis and nanostructuring. In case of Au(100), different surface sensitive techniques show the lifting of stable hexagonal-reconstructed Au(100)-hex to the regular Au(100)-(1×1) structure at electrode potentials >0.55V in 0.01M HClO4 and at >0.32V in 0.1M H2SO4 [1]. Although various theoretical and experimental investigations have hitherto been carried out, the rationale behind the lifting of reconstruction is still not clear. In order to study this effect, we performed DFT calculations on Au(100)-hex and Au(100)-(1×1), first neglecting the electrolyte and studying the influence of the electrode potential by applying an external electric field. For both electrolytes (HClO4 and H2SO4) we were able to reproduce the experimentally measured transition potentials after correlating the applied electric field to the electrode potential using experimental capacity curves. While this already implies a major role of surface charging, we are now in the process of investigating the influence of ion adsorption. [1] D. M. Kolb, Prog. Surf. Sci., 51, 109 (1996).