Density functional study of the interaction of molecular oxygen with small neutral and charged silver clusters

Abstract

O 2 adsorption on small neutral, anionic and cationic silver clusters Ag n ( n = 1–7) has been studied by using the PW91PW91 density functional method. The adsorption energies of O 2 on the anionic and neutral clusters have an odd–even alternation pattern clearly, and our calculations give the same adsorption behavior of O 2 on silver cluster anions as the experimental measurements. The adsorption energies on the cationic clusters, instead, are generally smaller than those on the anionic and neutral clusters, and reach a local maximum at Ag 4 O 2 + . Natural bond orbital analyses show that electrons mostly transfer from silver atoms to molecular O 2 except for the smallest silver cluster cations ( n = 1–3).