Proton Transfer in Ionic Water Clusters

Abstract

How waterlike are ionic water clusters? Clusters with 10 to 100 water molecules are frequently used as model systems for reactions in aqueous solution. Concerted proton transfer, a key feature of liquid water, can be probed by observing the formation of HDO when D2O is used as a reactant (see scheme). Mass spectrometry shows that proton transfer occurs in H(H2O)n+, whereas the individual water molecules stay intact in (H2O)n− and O2(H2O)n−.