STRUCTURE AND BONDING OF SMALL STOICHIOMETRIC LITHIUM-OXIDE CLUSTERS

Ground-state properties of stoichiometric lithium oxide clusters Li2nO n (n less than or equal to 6) are studied by means of ab initio molecu lar-dynamics simulations, in conjunction with a global optimization st rategy. For each n value, several stable isomers are found, presenting a remarkable variety of bonding configurations. We analyze the atomic structure, the local coordination, the bond lengths, and the relative stability of these clusters. By defining a mean bond length - average d over all atoms having the same coordination number - we show that it is possible to characterize the global bonding Properties of a Li2nOn cluster at given n despite the structural differences among the vario us isomers. For some of them, energy barriers can be easily overpassed , making possible a dynamical equilibrium among a few configurations i n a temperature range of some hundred K above room temperature.