Molecular Dynamics Study Of The Microscopic Structure Of Aluminum Clusters

In this paper, we have investigated the ground-state structures and HOMO-LUMO gaps of the Aln clusters using full-potential linear-muffin-tin-orbital molecular-dynamics(FP-LMTO MD) based on first principle. The FP-LMTO MD method is one of the best methods for calculating the geometrical and electronic structures of crystals (including crystal surfaces and clusters) in the world at the present time. This method gives high precision to the calculation results because of full potential adopted. In this paper, using this method, we have found some new ground states and a series of stable structures, including almost all the structures reported before.We have performed calculations of Al13, Al13+, and Al13- clusters using the method mentioned above. We found the most stable structures of Al13 and Al13-icosahedrons, while the ground-state structure of Al13+ is other structure. For Al19 clusters, besides the double icosahedral structure, which was considered to be the most stable structure of Al19 by early studies, a set of new isomers, the binding energies of which are a little bit larger than that of the double icosahedral structure in our calculation, are found. However, the energy differences between these isomers are so small that it is hard to take a single configuration as the ground-state of Al19 cluster.For Al20 clusters, A set of new low-lying energy structures including a new lowest energy structure, were found in our calculation. The waist-capped double icosahedral structure, which was considered as the global minimum previously, is merely one of the low-lying structures. For Al21-Al29, we also have done a lot of calculations, some new ground state structure are found and some are the same as the former report.We also calculated the density of states (DOS) of the ground state structures of Aln clusters, discussed the HUMO-LUMO gap of Aln clusters and found Aln clusters may present metallic properties.