Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 37: Posters: Plasmonics, Electronic Structure and Spin-Orbit Interaction, Semiconductor and Insulator Surfaces, Nanostructures

O 37.84: Poster

Dienstag, 1. April 2014, 18:30–22:00, P2

Characterization of the adlayer formation of CO on the NaCl(100) surface based on diffuse LEED intensities — •Jochen Vogt and Birgit Vogt — Chemisches Institut der Uni Magdeburg, Magdeburg, Germany

Changes of the diffuse background in low-energy electron diffraction patterns can be used to characterize the stages of adlayer formation on well-ordered surfaces. Using the MCP-LEED technique, such experiments are also possible with bulk insulators without extensive surface charging. Although a helium atom diffraction study reported a p(1×1) symmetry of the system CO/NaCl(100) at temperatures above 35 K [1], superstructure features of the low-temperature p(2×1) phase are visible in LEED diffraction patterns well above this temperature. At 40 K, the subtraction of subsequently recorded LEED patterns reveals the formation of a diffuse background in the initial stages of the adlayer growth, consistent with an earlier proposed adsorption of CO at isolated sites [2]. The superstructure peels off from the background at a coverage of about half a monolayer. With the intention to develop a structure model of the disordered adsorbate, we present calculated diffraction patterns based on energy optimized local geometries. [1] D. Schmicker, J. P. Toennies, R. Vollmer, H. Weiss, J. Chem. Phys. 95 (1991), 9412 [2] C. Noda, G. E. Ewing, Surf. Sci. 240 (1990), 181