Europhys. Lett.
Volume 74, Number 6, June 2006
Page(s) 1032 - 1038
Section Condensed matter: structural, mechanical and thermal properties
Published online 12 May 2006
Europhys. Lett., 74 (6), pp. 1032-1038 (2006)
DOI: 10.1209/epl/i2006-10050-8

Polarization-dependent resonant anomalous surface X-ray scattering of $\chem{CO/Pt(111)}$

A. Menzel1, Y. V. Tolmachev1, K.-C. Chang1, V. Komanicky1, Y. S. Chu2, J. J. Rehr3 and H. You1

1  Argonne National Laboratory, Materials Science Division 9700 S. Cass Ave., Argonne, IL 60439, USA
2  Argonne National Laboratory, Experimental Facility Division 9700 S. Cass Ave., Argonne, IL 60439, USA
3  University of Washington, Department of Physics P.O. Box 351560, Seattle, WA 98195, USA

received 24 January 2006; accepted in final form 19 April 2006
published online 12 May 2006

Polarization dependence of resonant anomalous surface X-ray scattering (RASXS) was studied for interfaces buried in electrolytes and in high-pressure gas. We find that RASXS exhibits strong polarization dependence when the surface is only slightly modified by adsorption of light elements such as carbon monoxide on platinum surfaces. $\sigma $- and $\pi$-polarization RASXS data were simulated with the latest version of ab initio multiple scattering calculations (FEFF8.2). Based on the simulation, we find that Pt layer to C distances in the ($2\times 2$)-3$\chem{CO}$ structure are $\sim 2.0\un{\AA}$ and $\sim 1.6\un{\AA}$ for atop $\chem{CO}$ and 3-fold $\chem{CO}$, respectively. Some considerations are presented for the origin of the polarization dependence in RASXS.

61.10.-i - X-ray diffraction and scattering.
68.35.Ct - Interface structure and roughness.
82.45.Jn - Surface structure, reactivity and catalysis.

© EDP Sciences 2006