SURFACE COVERAGE STUDIES OF THE AL-13 ICOSAHEDRON BY LI USING DENSITYBASED MOLECULAR-DYNAMICS

Density based molecular dynamics has been used to investigate the grou nd state structures of heterogeneous binary clusters Al13Lin, n = 1, 2 , 3, 4, 10, 19, 20, 21. Some of these structures have also been invest igated by full Kohn-Sham based calculations. Our earlier investigation s have shown that in the Al-Li cluster, the ground state configuration s are the ones where the Al atoms form a core around which the Li atom s form a ''cage''. In the present work, we have chosen the well-known Alla icosahedron as the surface over which we study the evolution of t he surface coverage as the number of Li atoms increases. On the basis of the earlier work, we expect that the Al13Li20 cluster would be the most stable and indeed our simulations do yield such a novel fivefold symmetric stable structure formed out of purely metal atoms. This icos ahedral substrate is also used to study the coverage of the aluminum s urface by lithium atoms. For a small number of Li atoms, these studies suggest that the Li-Li dimerisation is not particularly favored.