RgBeB: theoretical investigation of BeB and its rare gas capability.

A series of BeB and its rare gas (Rg) containing complexes RgBeB (Rg = He-Rn, n = 1-6) have been predicted theoretically using the B3LYP, MP2, and CCSD(T) methods to explore structures, stability, charge distributions, and nature of bonding. Both BeB and RgBeB are the global minima on the potential energy surfaces. In the RgBeB complexes, the dissociation energy drops with the increase in number of Rg. Natural bond orbital (NBO) and topological analysis of the electron density (AIM) show that the Rg-Be bonds for Kr-Rn have some covalent character. The Rg-Be bond is stabilized dominantly by the Rg → BeB σ-donation from the valence p orbital of Rg to the vacant valence LUMO orbital of RgBeB. Besides, other two π-donations also play important roles in stabilizing the Rg-Be bonds.