First-principles local-orbital density-functional study of Al clusters

Abstract

We report ab initio molecular-dynamics simulations of small aluminum clusters, ${\mathrm{Al}}_{\mathit{n}}$ of n=2--6 and 12, 13, 55, and 147, using the density-functional, local-orbital method of Sankey. Equilibrium structures and total energies were calculated and compared with experiment and the predictions of other calculations. The minimum energy structure of ${\mathrm{Al}}_{13}$ and ${\mathrm{Al}}_{55}$ are found to be distorted icosahedrons, whereas that of ${\mathrm{Al}}_{147}$ appears to be a slightly distorted cubo-octahedron. The vibrational density of states was calculated for most of these clusters. We also performed embedded-atom method calculations for ${\mathrm{Al}}_{13}$, ${\mathrm{Al}}_{55}$, and ${\mathrm{Al}}_{147}$ and compared these calculations to the ab initio calculations.