A COMPARATIVE-STUDY OF CO AND NO CHEMISORPTION ON CU2O(111) AND AG2O(111) NONPOLAR SURFACES

The chemisorption of XO (X = C and N) on the isoelectronic and isostru ctural M2O(111) (M = Cu and Ag) non-polar surfaces has been theoretica lly investigated. Two molecular orientations, X-and O-down, have been considered. Total energy calculations indicate that the X-down bonding is stronger than O-down for both substrates. Both OX --> Cu(I) sigma donation and Cu(I) --> XO pi backdonation participate to the adsorbate -substrate bonding, while the OX-Ag(I) interaction is characterized by a poorer OX --> Ag(I) sigma donation and a negligible Ag(I) --> XO pi backdonation. (C) 1997 Elsevier Science B.V.