Fragmentation channels and their relationship to magic number studies of microclusters

The energetics associated with the fragmentation of both neutral and ionized microclusters of lithium and sodium atoms have been studied using the self-consistent-field molecular orbital theory. We show that the energetically most favorable fragmentation channel is the one that contains, as one of the fragments, the most stable cluster. The latter is governed by the electronic structure and is related to the observed magic numbers. We also show that clusters "born neutral" or "born ionized" would exhibit different magic numbers.