Li and Be clusters: Structure, bonding and odd-even effects in half-filled systems

Abstract

We compare and contrast the structure and bonding aspects in clusters of alkali and alkaline earth metals: Li and Be respectively. The binding energies for both the clusters increase with increase in cluster size, however, for Be, the binding energies increase much rapidly due to stronger cooperative phenomenon. For the high spin Li clusters, the binding energies are moderate and show a remarkable odd-even effect. Similar oscillations are also observed in their π-electron binding energies. The origin of such effects is traced to the ferromagnetic interactions arising from the unpaired electrons for the high spin clusters. On the contrary, for Be, no such odd-even effects are observed due to absence of unpaired electrons.