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Surface states play a crucial role in the interaction of adsorbates on metallic substrates. On the one hand surface states influence the physisorption potential as well as the dissociation barrier and even the self-assembly of adsorbates [1, 2]. On the other hand surface states can be modified by adsorbates like alkali metals, rare gases and other noble metals [2-4].
We report about the modification of the Cu(110) Shockley surface state by the adsorption of pentacene. With increasing pentacene coverage the surface state is shifted to higher binding energies and becomes more populated at a coverage of one monolayer, indicating an electron transfer from the pentacene ad-layer to the surface state. The results will be discussed regarding different modification mechanisms and will be compared to the modification of the Au(111) surface state by the adsorption of PTCDA (3,4,9,10-perylene tetracarboxylic dianhydride, C24H8O6) [5].
[1] J. Repp, F. Moresco, G. Meyer, and K.H. Rieder; PRL 85, 2981 (2000)
[2] F. Forster, A. Bendounan, J. Ziroff, and F. Reinert; Surf. Sci. 600, 3870 (2006)
[3] F. Forster, G. Nicolay, F. Reinert, D. Ehm, S. Schmidt and S. Hüfner; Surf. Sci. 532-535, 160 (2003)
[4] D. Popovic , F. Reinert, S. Hüfner, V. G. Grigoryan, M. Springborg, H. Cercellier, Y. Fagot-Revurat, B. Kierren, and D. Malterre; PRB, 72, 045419 (2005)
[5] N. Nicoara, E. Román, J. M. Gómez-Rodríguez, J. A. Martín-Gago, and J. Méndez; Org. Electron. 7, 287 (2006)
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