Structures and stabilities of ScBn (n = 1-12) clusters: an ab initio investigation.

The geometries, stabilities, and electronic properties of ScBn (n = 1-12) clusters have been systematically investigated by using density functional theory B3LYP method and coupled-cluster theory CCSD(T) method. It is found that the ground state isomers of ScBn have planar or quasi-planar structure when n ≤ 6, which can be viewed as a B atom of the corresponding Bn+1 cluster is substituted by a Sc atom. From n ≥ 7, the ground state isomers favor nest-like structure, in which the Sc atom sits on a nest-like Bn cluster. The calculated second-order differences of energies manifest that the magic numbers of stability are n = 3, 7, 8, 9 and 11 for the ScB n clusters. Further analysis indicates that the ScB7 cluster with C 6v symmetry represents the outstanding stable ScBn cluster, as confirmed by its electronic structure and molecular orbitals.