Chlorine Molecule Adsorption On Small Au Clusters

ABSTRACT

The reaction mechanism and effects of Cl2molecule adsorption on the electronic and geometric structure of small cationic neutral and anionic Au (n = I — 6) clusters has been investigated using density functional theory in the generalized gradient approximation (GGA), PW91 and the hybrid functional B3LYP. The structures of the optimized geometries have shown remarkable propensity for planarity. Our results also have shown that the adsorption energies of Cl2 molecule on cationic clusters decreased as cluster size increases, the neutral cluster exhibited an even — odd trend which favours dissociative adsorption for odd cluster numbers, while the adsorption energies for anionic clusters is between 3.5 — 4.4 eV. The clusters of different charge state have shown a pronounced sensitivity to cluster size and charge state. Generally, a remarkable adsorption was observed for all charge states with adsorption energy values above 0.2 eV. The adsorption of Cl2molecule on Au clusters can be characterized by the frequencies of Au — Cl vibrations and the weakening and elongation of Cl — CI bond which are essential factors of adsorption.