Surface relaxation and surface stress of Au(1 1 1)

• Published in: Surface science Vol. 513; no. 2; pp. 263 - 271
• Main Authors: Nichols, R.J, Nouar, T, Lucas, C.A, Haiss, W, Hofer, W.A
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 20-07-2002; Amsterdam Elsevier Science; New York, NY
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Density functional calculations; Dynamics; vibrations; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Gold; Physics; Solid-fluid interfaces; Surface and interface dynamics and vibrations; Surface and interface electron states; Surface relaxation and reconstruction; Surface states, band structure, electron density of states; Surface stress; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); X-ray scattering, diffraction, and reflection; Gold; Density functional calculations; Surface relaxation and reconstruction; Surface stress; X-ray scattering, diffraction, and reflection; Liquid solid interface; Surface electron state; Theoretical study; Experimental study; Structure relaxation; Surface stresses; Surface structure; Sulfuric acid; Cyclic voltammetry; Jellium model; Surface reconstruction; Electronic structure; Aqueous solutions; Transition elements; Crystal electrode; Density functional method; Ab initio calculations; Surface dynamics
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/S0039-6028(02)01510-8

Changes in surface stress and in the top-layer expansion of Au(1
1
1) electrodes in sulfuric acid have been measured as a function of electrode potential by combining surface stress and X-ray diffraction measurements. Both are linear functions of interfacial charge in the electrode potential range of changing anion coverage. Over this range the surface stress changes by −0.5 N
m
−1 (compressive direction), while the outward top-layer relaxation decreases from +1.5% to +0.2%. The surface stress changes can be rationalized in terms of a jellium model, while ab initio simulations are needed to explain the top-layer expansion. These simulations yield +1.3% relaxation for the uncharged gold surface, in good agreement with the X-ray diffraction measurements. They also demonstrate that the outward relaxation of the surface is curbed in the presence of an electron withdrawing adsorbate (Cl), which mimics the effects of positive surface charging.