Calculation of Electronic Structure of Aluminum and Sodium Clusters Using the Method of Linear Combination of Atomic Orbitals.
The Linear Combination of Atomic Orbitals ( LCAO ) cluster method has been successfully applied to calculate the electronic structures of aluminum clusters containing 19, 43 and 79 atoms and of sodium clusters containing 15 and 59 atoms. The properties of metallic clusters are used to compare with those of bulk metals. The conduction band widths of each cluster was obtained. The occupied conduction band widths of various clusters were used to compare with those of bulk metal and were found to approach to bulk values. The occupied conduction band widths of 6-shell clusters were very close to those of bulk metal. The density of states of aluminum and sodium clusters are found to have the parabolic shape of a free-electron-like metal. The surface states of various clusters were studied. The analysis of conduction states shows that higher energy (close to Fermi level) electrons tend to localize in the outer shells, especially in the top two shells, of the clusters. The large clusters such as 6-shell metallic clusters have clear surface. Their outer three shells can be considered as surface shells. The charge density distribution across through the boundary of the surfaces were studied. The Friedal oscillations are found to exist at the surface of the clusters. The charge density distributions of different clusters were plotted and found to be very spherically symmetric. All of those properties are the same for aluminum metallic clusters with F.C.C. cluster structure and sodium metallic clusters with B.C.C. cluster structure. Those properties are proven to be independent of cluster structure.
- Pub Date:
- Physics: Condensed Matter