Theoretical study of NO adsorption on neutral, anionic and cationic Ag8 clusters

Density functional theory calculations have been carried out to study the process of NO adsorption on neutral, anionic and cationic Ag-8 clusters. Three cluster types have been considered in our study: D-2d and T-d structures are the most stable isomers in gas phase and C-1 structure, which has the geometry of the most stable isomer adsorbed on rutile TiO2 (1 1 0) surface. Adsorption energies, N-O bond lengths and corresponding N-O vibration frequencies have been calculated for all structures. It has been shown that in the case of NO interaction with D-2d structure the corresponding adsorption energies grow in the following order: E-ads(cation) < E-ads(neutral) < E-ads(anion). The same regularity has been observed for NO interaction with silver tetramers in our previous study. For the T-d structure the highest adsorption energy is also observed in case of anionic complex. However, for C-1 structure other dependence has been observed: E-ads(anion) < E-ads(cation) < E-ads(neutral). The adsorption of NO on neutral Ag-8 cluster (C-1 structure) is characterized by the largest N-O bond elongation which should be useful for NO fragmentation process. (C) 2010 Elsevier B.V. All rights reserved.