Molecular beam induced changes in adsorption behavior of NO on NiO(111)/Ni(111).

We have examined the adsorption behavior at approximately 110 K of NO on NiO(111) overlayers prepared on a Ni(111) substrate. High-resolution electron-energy-loss spectroscopy shows fundamental changes in the vibrational spectrum for the beam dosed surface in comparison with the background dosed surface. Three vibrational peaks are observed after beam dosing, two of which are not observed after conventional background dosing. The peaks can be assigned to NO stretches for a previously observed NO state, a new NO bonding geometry, and a new NO2 surface species, previously unobserved under NO dosing. The difference is accounted for by increased NO uptake due both to kinetically activated adsorption and to increased exposure.