Berlin 2008 – scientific programme

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O: Fachverband Oberflächenphysik

O 62: Metal Substrates: Adsorption of Inorganic Molecules

O 62.8: Talk

Thursday, February 28, 2008, 11:15–11:30, MA 042

New adsorption states of carbon monoxide on Cu(110) — •Erkan Demirci and Adolf Winkler — Graz University of Technology, Institute of Solid State Physics, Graz, Austria

The adsorption of carbon monoxide on a Cu(110) surface has been investigated by Auger electron spectroscopy (AES), thermal desorption spectroscopy (TDS) and low energy electron diffraction (LEED). The carbon monoxide desorption spectra as known from literature exhibit only a peak at 210K (α state) when adsorption takes place at T = 100 K -150 K, correlated with a (2x1) superstructure [1,2]. When CO is adsorbed at 180 K and using high enough exposure the TDS clearly shows additional peaks at 245 K, 290 K and 355 K (β₁, β₂, β₃ states). The population of these peaks is adsorption temperature dependent. The peak maxima of β₁ and β₂ shift to higher temperature with increasing coverage, in contrast to the α and β₃ peaks, which show coverage independent peak maxima. LEED shows a (1x2) superstructure when CO is adsorbed at 300 K. From these results we conclude that a missing row reconstruction is induced by CO, which leads to the new adsorption states. Additional quantitative TDS and angle resolved TDS measurements were performed to support this idea. Financial support by the Austrian Science fund (FWF), Proj. No. P 20026 is gladly acknowledged.

[1] C. Harendt, J. Goschnick and W. Hirschwald, Surf. Sci. 152/153 (1985) 453

[2] K. Horn, M. Hussain and J. Pritchard, Surf. Sci. 63 (1977) 244