Atomic and electronic shells of Al77

We have carried out a first-principles calculation on the atomic and electronic shell structures for the experimentally characterized Al-77 The onionlike Al-77 structure can be described by a stable Al-13 inner core covered by a two-layer atomic shell. The stability of Al-77 is confirmed by structural optimization and electronic structure calculations. The interaction between Al-77 and its ligands is found to be ionic like. Our results on the electronic structure provide important information on electronic shell structures in large Al clusters.