Probing the structural evolution, electronic and vibrational properties of magnesium clusters doped with two lithium atoms.

[Display omitted] Bimetallic clusters received tremendous interest because the unusual physicochemical properties vary sensitively depending on their geometry, size, and composition. Here, we combined an efficient CALYPSO structural searching code and DFT calculations to study the structures and properties of magnesium clusters doped with two Li atoms, Li 2 Mg n (n = 1–11). Compared with pure Mg n clusters, it is found that Li doping induces a significant influence on the geometry and stability of the host. The structures of Li 2 Mg n are present a 2D to 3D transition at n = 3, slightly later than pure and single Li doped magnesium clusters. Localized sites of two Li atoms change from the convex position to the external capped position at n = 11. All positive charges on Li atoms illustrate a charge transfer from Li to Mg in doped clusters. Analysis of internal charges on the atomic orbitals shows an increased metallicity for Li 2 Mg n with increasing cluster size. Two triangular bipyramid structures, Li 2 Mg 3 and Li 2 Mg 9 , were uncovered and proved to be the magic number ones with outstanding stability. The study of molecular orbitals and bonding nature implies that their higher stability is associated with the 1S21P6 and 1S21P61D102S2 closed-shell together with more strong Li-Mg bonds caused by sp hybridization. The simulated IR and Raman spectra could provide additional ways to identify the structure of these clusters in the following experiments. [ABSTRACT FROM AUTHOR]