Model analysis of the fragmentation of large H $\mathsf{_{2}}$ O and NH $\mathsf{_{3}}$ clusters based on MD simulations

The fragmentation statistics of (H2O) n and (NH3) n clusters (n = 100-1000) is investigated by MD simulations at different temperatures. The fragment size distributions are found to be well described by power laws over a wide range of excitation energies. The maximum fragment size depends linearly on the cluster size. A compact analytical model, implying the maximum fragment size and the power law exponent, is shown to fairly fit the average fragment size profiles. Measurements are carried out for the maximum fragment sizes after electron impact ionisation for water and ammonia clusters in the size range of n = 50 to 2100. The measured linear dependence on cluster size is used to estimate the fragment size distributions.