Nonmonomer Evaporation from Molecular Clusters at Low Temperature via a Ring-Reconstruction Mechanism

Evaporation plays a pivotal role in the evolution of molecular clusters, particularly in processes such as atmospheric particle nucleation. Most previous studies have focused on monomer evaporation, leaving the role of nonmonomer evaporation (fragmentation) largely unexplored. In this study, we introduce a multichannel dynamical nucleation theory (MC-DNT) to investigate nonmonomer evaporation systematically. We observe that nonmonomer evaporation of water clusters becomes non-negligible only at high temperatures, whereas that of ethanol clusters can be dominant even at low temperatures. More intriguingly, contrary to the common expectation that it increases with temperature, we find that nonmonomer evaporation peaks at lower temperatures for relatively large ethanol clusters. Such counterintuitive behavior is attributed to a ring-reconstruction mechanism. These results advance our understanding of molecular cluster dynamics.