Microsolvation of the chlorine oxide anion and chlorine oxide radical: Structures and energetics of the ClO− · (H2O)n and ClO · (H2O)nn = 1-4 clusters

Counterpoise corrected geometries, absolute energies, and vertical detachment energies of the ClO− · (H2O)nn = 1-4 clusters were determined for the first time using high-level ab initio [up to CCSD(T)] and density functional theory calculations. For the n > 1 clusters, a number of low-energy, isomeric structures are obtained. The global minima structures are characterized by water hydrogen bonds to the oxygen of ClO−, with the Cl protruding from the cluster surface. By contrast, the neutral ClO · (H2O)nn = 1-4 cluster structures are controlled by water-water interactions, with ClO being only weakly bound. Implications for the atmospheric chemistry and photodetachment spectroscopy of these species are briefly discussed.

Anionic ClO− · (H2O)nn = 1-4 clusters display dramatically different solvation motives to the neutral analogues. The anionic clusters are characterized by water hydrogen bonds to the oxygen of ClO−, while the neutral cluster structures are controlled by water-water interactions with ClO being only weakly bound. Substantial ionization induced geometry changes are therefore predicted.