A DFT investigation on ZnO clusters and nanostructures

The stable structures of the (ZnO)n (n = 1-12) were fully optimized with Gaussian 98 program package at B3LYP/6-31G level, and we found that, for n = 1-5, the ring structures is more stable, but for n > 5, the three-dimensional structures is more stable than the ring ones. But the stable ring geometries for n = 9 were not gotten, and when n > 10, the ring structures no longer exist. Our calculation also shows that, with the growth of n the 3D structures are more favorable in energy, and the Zn and O atoms tend to adopt higher coordination numbers. Moreover, the stimulated IR spectra can help us distinguish the ring structures from the cubic or hexagonal packing ones.