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 Al₇₇. The onionlike Al₇₇ structure can be described by a stable Al₁₃ inner core covered by a two-layer atomic shell. The stability of Al₇₇ is confirmed by structural optimization and electronic structure calculations. The interaction between Al₇₇ 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.