Proton and Deuteron Transfer Reactions in Molecular Nanoclusters

Proton and deuteron transfer rates and mechanisms are studied in polar molecular nanoclusters. The cluster environment strongly influences the reaction rate and the nature of these changes is studied as a function of the cluster size. The stabilities of the covalent reactant and polar product states change with cluster size and this effect alters both the equilibrium properties and transfer rate. The proton and deuteron are light quantum particles and the quantum character of the rate process is reflected in the magnitude of the kinetic isotope effect. Our mixed quantum–classical rate simulations indicate that the magnitude of the isotope effect decreases as the cluster size increases. More generally, our study shows how quantum effects combined with structural nanosolvation effects can lead to changes in reaction rates and mechanisms which should be applicable to many quantum charge transfer reactions in molecular nanoclusters.