Adsorption of CO on a pseudomorphic palladium monolayer on Mo(l l0)

Adsorption of CO on a Pd monolayer (ML) supported on Mo(ll0) has been studied using low energy electron diffraction (LEED), temperature programmed desorption (TPD), and high resolution electron energy loss spectroscopy (HREELS). Three ordered CO substructures denoted as (~ Jl) (-21 ~), and (~ ~l) are observed with LEED. The binding energy of CO on the 1.0 ML Pd/Mo(ll0) surface is reduced by 12 kcal/mol relative to the Pd(lll) surface, consistent with previous results for supported palladium monolayers on other substrates. Two vibrational states of CO are observed near 1950 and 2050 cm -1, with the feature at the lower wavenumber having the smaller binding energy.