Orientational Effects on the Electronic Structure and Polarization in Sc₃N@C₈₀

Of particular interest in metal encapsulating fullerenes such as Sc₃N@C₈₀ is not just how the charge is transferred between atoms of the metal nitride core and the carbon cage but how the orientation of the core impacts the electronic structure of the entire molecule. A channel for the electron backdonation is identified which leads to a charge hole on the fullerene cage, just below the valence level, which is pinned to the orientation of the metal nitride. This electron hole is overcompensated by paired electron charge at deeper levels. Reorienting the metal nitride inside the cage results in a change in the surface charge distribution below the valence level and the lowest energy empty levels coupled to the metal ions. The charge separation between the metal nitride core and the carbon cage drives changes in the polarizability of the molecule depending on the orientation of the core. Furthermore, it is found that the electron affinity depends on the orientation of the metal nitride core. This is the result of the overlap between the scandium ions' d-orbitals with the fullerene cage 6:6:6 p orbitals. The electronic and geometric structures of the Sc₃N@C₈₀ metallofullerene are examined by using the density functional theory, and the findings are corroborated by an analysis of the density of states combined with charge density plots.