Competing pathways for MgO, CaO, SrO, and BaO nanocluster growth

A comparative structure and stability study is performed on a sequence of (MgO)n , (CaO)n , (SrO)n and (BaO)nclusters, 44n412. The B3LYP functional is employed to seek preferred cluster growth pathways. Similarstabilities are found for two growth strategies, one producing rock-salt-like structures, and a second whichemploys stacks of hexagonal (MO)3 rings. Structures based on hexagonal rings are slightly preferred in the caseof MgO and BaO, while for CaO and SrO the rock salt structural analogue prevails. The shift in isomer stabilityorder is discussed in terms of packing of spheres. The small magnitude of the atomic size difference for oxygenand the corresponding metal atoms in the cluster implies preference for the rock salt structure. Larger jDRAjresult in a preference for hexagonal ring-based structures