Solvation structure and stability of hypervalent NH4(CH3OH)m(NH3)n clusters

Ionization potentials (IPs) of NH4(CH3OH)m(NH3)n radicals produced by an ArF excimer laser photolysis of ammonia–methanol mixed clusters are determined by the photoionization threshold measurements. The observed IPs show the different evolutions with increasing the number of ammonia and methanol solvents. The IPs are also examined by ab initio calculations, which suggest that the hydrogen bond network is dominant in the case of adding methanol. Moreover, the lack of NH 4 ( CH 3 OH ) m + (m ⩾ 1) signals indicates that they have very short lifetimes (<4 ns) due to a fast elimination of hydrogen-atom from NH4 radical via tunneling.