Ground state geometries and energetics of AL_nLi (n=1,13) clusters using ab initio density-based molecular dynamics

Abstract

Based on orbital-free ab initio molecular dynamics calculations, the geometries and energetics of lithium-doped aluminium clusters (Al_nLi, N=1, 13) have been investigated. It is seen that, a single impurity of Li affects the geometries of small (n < 6) clusters, and this effect is less pronounced for larger clusters. The results suggest extra stability for the Al₃Li, Al₆Li and Al₁₃Li clusters, which are in contrast with our earlier results on Li_nAl. The results indicate that the Li atom segregates to the surface of the aluminium cluster and prefers to form a tetrahedron, wherever possible, with one of the triangular faces of Al atoms. In particular, for Al₁₃Li, the Al₁₃ core takes the most symmetric icosahedral form with the Li atom occupying the outer 'hollow-site'.