Theoretical insight into the coordination number of hydrated Zn ^{2 +} from gas phase to solution

The micro-hydration of Zn ^{2 +} was studied for clusters growing from 6 to 216 water molecules to derive the zinc coordination number as a function of cluster size and temperature and to bridge the gap between recent experimental values determined in the gas phase and in solution. The increasing complexity of potential energy surfaces requires extensive exploration, which was addressed using polarizable molecular dynamics with extended time frames. Reliable coordination numbers have been obtained for the different cluster sizes, at temperatures ranging from 200 to 300 K. The results provide a global picture of a growing coordination number as a function of cluster size, from ca. 5 for small gaseous clusters to 6 in bulk water.