Figure 1. (MgO)16 and (ZnO)16cluster models. (Color description Mg: yellow; O: red; Zn: cyan)
As shown in Fig. 1, the optimized structure of the
(ZnO)16 cluster exhibits a feature similar to those of
(MgO)16. Vibrational frequency calculation confirms that
the structure of (ZnO)16 (Fig. 1) corresponds to the
potential energy minimum. To check the possibility of other minima
structures of (ZnO)16, we further applied one of the
global optimization algorithms [32] implemented in
the atomic simulation environment (ASE) program.[33,34] The result of the global optimization
indicates that the structure shown in Fig. 1 is a global minima.