Ab initio molecular orbital study on the properties of ClO+(H2O)n cluster ions

Minimum energy geometries, harmonic vibrational frequencies, and stepwise binding energies have been obtained for the cluster ions ClO+(H2O)n, with n = 1-3, at the MP2/aug-cc-pVTZ level. The ground-state structure of ClO+(H2O), contacting by a weak Cl⋯O bond, exhibits a C2v symmetry. When a second water molecule is added, a new solvation shell is formed via a hydrogen bond. Our investigations indicate that a third water molecule attaches to the first water molecule and completes the second solvation shell. The stepwise hydration energies are found to be −20.72, −13.12, and −11.47 kcal/mol for n = 1, 2, 3, respectively, after zero point energy (ZPE) corrections, as well as counterpoise corrections for basis set superposition errors (BSSE), suggesting that the radical complex should be experimentally observable.