Evolution in the structural and bonding properties of Aluminum-Lithium clusters

We present a systematic study of the geometry, energetics, electronic structure and bonding in various Al-Li clusters viz. AlnLin (n=1-11), Al2 , Al2− 2 , Al2Li, Al2Li−, and Al6Li8 using Born-Oppenheimer molecular dynamics method within the framework of density functional theory. The growth patterns in these cluster are found to be divided in two broad categories: the first consisting of a quinted roof of Al2Li2 (n=2-4) and the second consisting of a pentagonal ring (n=7-9). A covalent bonding between Al-Li in Al2Li2 is seen, whereas, in larger clusters, it is ionic. A three dimensional growth of the Al cluster in Al2− 4 , Al5Li5, and Al6Li8 leads to a transition from localized to delocalized bonding. In clusters with more than six Al atoms, the eigenvalue spectrum is divided into two groups: a lower group of jellium-like states and a higher group of localized bonds arising out of p complex. Thus, a mixture of localized, delocalized, and ionic bonding is seen in these clusters. Finally, we have discussed the tetravalent behavior of Al atoms arising due to a charge