Comparison Between Electride Characteristics of Li₃@B₄₀ and Li₃@C₆₀

Density functional theory (DFT) based computation is performed on the endohedrally encapsulated Li₃ cluster inside the B₄₀ and C₆₀ cages namely, Li₃@B₄₀ and Li₃@C₆₀. For both these systems, the Li-Li bond lengths are shorter than that in the free Li₃ cluster. Due to confinement, the Li-Li vibrational frequencies increase in both the systems as compared to that in the free Li₃ cluster. Thermodynamically, the formation of these two systems is spontaneous in nature as predicted by the negative values of Gibbs' free energy changes (ΔG). For both the systems one non-nuclear attractor (NNA) is present on the middle of the Li₃ cluster which is predicted and confirmed by the electron density analysis. The NNA population and the percentage localization of electron density at the NNA of the Li₃@C₆₀ system are higher than that in the Li₃@B₄₀ system. At the NNA the values of the Laplacian of electron density are negative and an electron localization function basin is present at the center of the Li₃ cluster for localized electrons. Both systems show large values of nonlinear optical properties (NLO). Both the Li₃ encapsulated endohedral systems behave as electrides. Electrides have low work function and hence have a great potential in catalytic activity toward the activation of small molecules (such as CO₂, N₂). Even some electrides have greater catalytic activity than some well-studied metal-loaded catalysts. As the systems under study behave as electrides, they have the power to show catalytic activity and can be used in catalyzing the activation of small molecules.