Electrostatic interactions between coadsorbed Xe and CO

By measuring vibrational spectra of CO in the presence of coadsorbed Xe on Ru(001) we find that Xe induces CO stretch frequency downshifts as large as 38 cm-1. The frequency shifts are explained with a theoretical model based on the electrostatic interaction between Xe and CO. We suggest that xenon atoms can be used generally to probe electrostatic interactions and estimate contributions from electrostatically induced frequency shifts of coadsorbed molecules and atoms. © 1990.