Carbon monoxide induced ordering of adsorbates on the Rh(111) crystal surface

Abstract

We find that the coadsorption of CO with ethylidyne, propylidyne, acetylene, fluorobenzene, benzene, and sodium on the Rh(111) surface induces ordering in the adsorbed overlayer. This phenomenon has been studied using HREELS, LEED, and TDS. HREELS Indicates that the adsorbates maintain their molecular integrity when coadsorbed with CO though a change In adsorption site sometimes occurs. In all cases, the C-O stretching frequency of coadsorbed CO is substantially reduced from that of CO adsorbed on clean Rh(111) and ranges from 1410 cm −1 for CO coadsorbed with sodium to 1790 cm −1 for CO coadsorbed with ethylidyne.