The interaction of a single H 2 O molecule on selected ZnO nanoclusters is investigated by carrying out calculations based on the density-functional theory at the hybrid-GGA (B97-2) level. These clusters have ring, drum, tube and bubble shapes and their physical properties like the binding energy and the band gap energy depend strongly on the shape and size of the cluster. Depending on the stability of the cluster, H 2 O show both chemisorption and dissociation on the surfaces of the clusters. We analyzed the effect of H 2 O adsorption on the properties of clusters of size n=12 via the density of state, HOMO–LUMO orbitals and the changes in the IR frequencies.