Structure and stability of small Li2 +(X2Σ+ g )-Xen (n = 1–6) clusters

Abstract

We have studied the structure and stability of the Li2+(X2Σ+g)Xen (n = 1–6) clusters for special symmetry groups. The potential energy surfaces of these clusters, are described using an accurate ab initio approach based on non-empirical pseudopotential, parameterized l-dependent polarization potential and analytic potential forms for the Li+Xe and Xe-Xe interactions. The pseudopotential technique has reduced the number of active electrons of Li2+(X2Σ+g)-Xen (n = 1–6) clusters to only one electron, the Li valence electron. The core-core interactions for Li+Xe are included using accurate CCSD(T) potential fitted using the analytical form of Tang and Toennies. For the Xe-Xe potential interactions we have used the analytical form of Lennard Jones (LJ6 - 12). The potential energy surfaces of the Li2+(X2Σ+g)Xen (n = 1–6) clusters are performed for a fixed distance of the Li2+(X2Σ+g) alkali dimer, its equilibrium distance. They are used to extract information on the stability of the Li2+(X2Σ+gXen (n = 1–6) clusters. For each n, the stability of the different isomers is examined by comparing their potential energy surfaces. Moreover, we have determined the quantum energies (D0), the zero-point-energies (ZPE) and the ZPE%. To our best knowledge, there are neither experimental nor theoretical works realized for the Li2+(X2Σ+gXen (n = 1–6) clusters, our results are presented for the first time.