A theoretical investigation of the relaxation effects induced on the ZnO(10(1)over-bar0) surface by the chemisorption of H-2 and CO

Density functional theory coupled to the molecular cluster approach is used to investigate the chemisorption of CO on the clean and Cu doped ZnO(10 (1) over bar 0) surface. Results pertaining to the dissociative interaction of H-2 with ZnO(10 (1) over bar 0) are also presented. Theoretical data include evaluation of surface relaxation upon chemisorption, optimized adsorbate geometries, adsorbate-substrate binding energies and adsorbate vibrational frequencies. According to experiment, the ZnO-CO interaction is found rather weak, while the Cu-CO bonding results definitely stronger. As far as the dissociative chemisorption of H-2 on ZnO(10 (1) over bar 0) is concerned, we find that the formation of strong Zn-H and O-H bonds implies the Zn-O bond breaking. Both vibrational parameters and adsorption energies reasonably agree with available experimental measurements. (