Sequential growth simulation of (NH3)n clusters (n = 2–8) in ultracold superfluid environment

The growth of ammonia cluster (NH3)n (n = 2–8) in He droplets was studied using a polarizable potential assuming ultrafast heat dissipation and preventing the rearrangement of cluster structures. Energies, structures and isomer statistical distributions were obtained showing that a few high energy isomers may form with a probability similar to low energy ones and that ammonia clusters behave differently from (H2O)n for n ⩾ 5. Guide by our theoretical analysis, we suggest the need for re-interpreting recent experimental IR spectra of (NH3)n in He droplets for 5 ⩽ n ⩽ 8.