Adsorption sites in coadsorption systems determined by photoemission spectroscopy: K and CO coadsorbed on Rh(111)
Date of Original Version
The adsorption sites of coadsorbed K and CO on the Rh(111) surface have been determined using high-resolution core-level spectroscopy, low-energy electron diffraction and site-resolved photoelectron diffraction. For both a (2 × 2)-2CO-1K and a (2√3 × 2√3)-6CO-1K structure, we find that the CO molecules occupy threefold hollow sites and the K atoms on-top sites, contrary to the adsorption sites of K (threefold hollow site) and CO (on-top site below 0.5 monolayers) if adsorbed alone on Rh(111). Deposition of K onto a CO precovered surface is found to induce large shifts towards lower binding energy of the C and O 1s core levels (∼0.7 eV for C 1s and ∼1.5 eV for O 1s). The major part of these shifts is shown to arise from the K-induced site change of the CO molecules. This finding may be of importance in the interpretation of XPS data of related co-adsorption systems. Finally, it is suggested that the C and O 1s binding energies provide useful fingerprints of the CO adsorption site also for co-adsorption systems. © 1998 Elsevier Science B.V. All rights reserved.
Strisland, F., A. Beutler, A. J. Jaworowski, R. Nyholm, B. Setlik, D. Heskett, and J. N. Andersen. "Adsorption sites in coadsorption systems determined by photoemission spectroscopy: K and CO coadsorbed on Rh(111)." Surface Science 410, 2-3 (1998): 330-343. doi:10.1016/S0039-6028(98)00361-6.