Structural determination of (Al2O3)n (n = 1–7) clusters based on density functional calculation

We obtained the geometrical structures of (Al2O3)n (n = 1–7) clusters via genetic algorithm plus density functional theory method. Benchmark calculations show that the B3LYP/6-311 + G* method is reliable compared to CCSD(T)/aug-cc-pVTZ. However, the basis sets have great effect on relative energies of different structures. The global minimum structures are kite-shaped, cage and tea-cozy in structure for n = 1, 2 and 3 respectively, disordered at n = 4 and 5. At n = 6 and 7, a number of lower-energy isomers are obtained compared to the most stable structures obtained by Rahane et al. (J. Phys. Chem. C 115 (2011) 18111–18121). With increasing cluster size, structures show preference of disorder and some new configurations are derived.