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

► Geometric structures of (Al2O3)n (n = 1-7) clusters are obtained. ► Several new structures are derived with the degree of structural disorder increasing at large cluster size. ► Some isomers are nearly degenerate in energy. > Benchmark calculations reveal that the B3LYP/6-311 + G* method is reliable. ► The basis sets have great impact on relative stability of different structures.