Molecular orbital calculations of the dissociative adsorption of a hydrogen molecule on a 14 atom nickel cluster

Abstract:

MINDO/SR molecular orbital calculations have been performed for the Ni14H2 system in order to study the various steps of the dissociative chemisorption process of H2 over nickel. Particular attention was placed in the determination of physisorbed "precursor" states. It was found that such states may occur at border sites of our model cluster and that dissociative chemisorption may take place preferentially over a two-fold nickel site. The present results indicate that starting from this site, dissociation occurs following an essentially barrierless path. Changes in both electronic and binding properties along the path were studied in order to determine the relative importance of the several factors affecting chemisorption. In this respect, the role of d orbitals has been carefully analyzed with reference to the changes in density of states. The present results also indicate that after dissociation, the hydrogen atoms may easily move away from the border, into the surface, through low-barrier potential energy channels. © 1985.

Año de publicación:

1985

Keywords:

Fuente:

scopus