Ab initio investigation of water clusters (H2O)n (n = 2-34)

Abstract

Various properties of typical structures of water clusters in the n = 2-34 size regime with the change of cluster size have been systematically explored. Full optimizations are carried out for the structures presented in this article at the Hartree- Fock (HF) level using the 6-31G(d) basis set by taking into account the positions of all atoms within the cluster. The influence of the HF level on the results has been reflected by the comparison between the binding energies of (H2O)n (n = 2-6, 8, 11, 13, 20) calculated at the HF level and those obtained from high-level ab initio calculations at the second-order Møller-Plesset (MP2) perturbation theory and the coupled cluster method including singles and doubles with perturbative triples (CCSD(T)) levels. HF is inaccurate when compared with MP2 and CCSD(T), but it is more practical and allows us to study larger systems. The computed properties characterizing water clusters (H2O)n (n = 2-34) include optimal structures, structural parameters, binding energies, hydrogen bonds, charge distributions, dipole moments, and so on. When the cluster size increases, trends of the above various properties have been presented to provide important reference for understanding and describing the nature of the hydrogen bond. © 2009 Wiley Periodicals, Inc.