Dynamics of solvation-induced structural transitions in mesoscopic binary clusters

Ion solvation dynamics following collision of K+ with mesoscopic water-ammo nia aggregates is investigated. Two processes determine the postcollision s tate of the clusters: First, a morphological transformation from a structur e characterized by a solid water core and a liquid-phase ammonia sheath int o a dumbbell-shaped cluster composed of a liquid water droplet attached to an ammonia subcluster containing the solvated ion. Second, evaporation cool s the cluster during and after the morphological change and this evaporativ e cooling is quantitatively characterized by determining the size-dependent rate constants for these complex clusters.