Dissociation pathways and binding energies of (LiH)nLi+ and (LiH)nLi+3 clusters

The metastable decomposition of hydrogenated lithium cluster ions (LiH)nLi+m(m=0, 1 and 3; n≤15) is studied by using a reflectron mass spectrometer. These clusters are found to decompose by evaporation of a LiH or a Li2H2 molecule. The binding energy of these clusters are determined, using a statistical model which has been adapted to mixed clusters. Comparison with other mixed clusters suggests that (LiH)nLi+ clusters form compact cubic structure similar to pieces of a crystal lattice. For (LiH)nLi+3 clusters, the dissociation channels are more surprising, and the localization of the two excess electrons is discussed, as well as the possible existence of an energy barrier for the dissociation.