Gas-phase stability of c-BN clusters

The stability of various cluster-sizes of H- and F-terminated c-BN, compared to corresponding clusters of h-BN, has been investigated theoretically using the ab initio molecular orbital method at the MP2 order of theory. For comparison, a corresponding investigation has also been performed for H-terminated diamond and graphite clusters. The cubic phase of C (diamond) was for al1 cluster-sizes investigated found to be more stable than cBN. The thermodynamically most stable phase obtained for the smallest BN cluster (containing one B and one N) was the hexagonal one. Both diamond and c-BN gas phase nuclei were found to be more stabilized for cluster-sizes larger than 6 C (or 3 B + 3 N) atoms. This stabilization energy tend to decrease drastically by using F (instead of H) as terminating species