Hydration shell structure of the OH−(H2O)n=1–15 clusters from a model potential energy function

The structural properties of the hydrated hydroxide ion are studied in terms of a many-body potential energy function that has been parameterized according to the experimentally determined [Arshadi et al., J. Phys. Chem. 74, 1475, 1483 (1970)] enthalpy and entropy changes for the first five association reactions of the ion with H2O. Clusters in the n=1–15 size range are examined through a canonical Monte Carlo simulation at T=297 K. The resultant structures, irrespective of the cluster size, are predominantly linear of the dendrite type, with the first shell consisting of two water molecules. Minimum energy structures at T=0 K for n=2 and 3 compare well with ab initio conformations.