Black body fragmentation of cationic ammonia clusters

We have carried out a systematic study of the blackbody radiation induced fragmentation of size-selected ionic ammonia clusters and compared it with that of the corresponding hydrates. Specifically, the Ag⁺ and H⁺ cation clusters were studied, with the fragmentation rate constants of the ions solvated with ammonia being found to exhibit the same overall linear dependence on the number of ligands n, which was previously observed for the corresponding hydrates as well as for a number of other hydrated ions. To facilitate the interpretation of the experimental observations, we have carried out DFT calculations of the cluster structures and of their harmonic frequencies and intensities. The observed fragmentation rate constants exhibit a satisfactory qualitative agreement with the computed rates of energy absorption from the blackbody infrared radiation background.