Structure and Stability of the Li+Xen and LiXen Clusters

We have studied the structure and stability of the ionic Li+Xen and neutral LiXen (n = 1-35) small clusters. The potential energy surface of the ionic cluster is described using additive potentials, which represent the pair interactions taken from the best available coupled cluster ab initio calculations. The V (Li) (+) (Xe) and VXe-Xe potentials have been fitted by Tang and Toennies and Lennard-Jones (LJ) forms, respectively. The structure of LiXen neutral clusters have been investigated using a model potential and ab initio calculations. We have used the Li+Xe potential in its ground state and fitted to the Tang and Toennies formula. The LiXen optimized geometry is, then, used for one electron self consistent filed calculation of the only alkali valence electron interacting with the Li+Xen cluster. In order to determine the geometry of Li+Xen and LiXen clusters and their isomers, the potential energy surface has been explored by the Monte Carlo basin Hopping method. Their relative stability was studied by evaluating the energy and the energy differences as function of number n of Xenon atoms in clusters. It was shown, for Li+Xen, that n = 4, 6, 10, 14, 16, 18, 20, 22, 24, 26, 28 and 30 are the most stable structures.