Theoretical study of hydrogen bonded clusters of water and cyanic acid: Hydrogen bonding in terms of the molecular structure

Ab initio and density functional calculations were used to analyze the interaction between a molecule of cyanic acid (HOCN) and up to 4 molecules of water at the B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) computational levels. The cooperative effect (CE) is increased with the increasing size of the studied clusters. Red shifts of the H-O stretching frequency for complexes involving HOCN as an H-donor were predicted. The strength of the hydrogen bonds in terms of molecular structures could be deduced from a comparison of HOCN-H2O with HCNO-H2O, HONC-H2O and HNCO-H2O HB clusters. The atom in molecules (AIM) method was used to analyze the cooperative effects on topological parameters.