A DENSITY-FUNCTIONAL STUDY OF CLUSTER REACTIVITY - AMMONIA REACTING WITH A FREE GA5AS5 CLUSTER

It is well known that the chemical reactivity of small gallium-arsenide clusters can be sensitive to cluster size and geometrical structure. We have performed ab initio calculations probing the interaction of NH3 with different sites of a free Ga5As5 cluster. Our results show that bonding tends to be strongest at gallium sites. Adsorption of NH 3 is found to induce strong relaxation of the cluster global geometry. The cluster sites are compared with sites on the (111) bulk surface of gallium arsenide, and the possibility for exploring the similarity between cluster reactivity and surface reactivity is discussed. © 1994 American Institute of Physics.