Superatom Molecular Orbitals of Endohedral C₈₂

Understanding superatom molecular orbital (SAMO) states in fullerene derivatives has been in the limelight ever since the first discovery of SAMOs owing to the fundamental interest in this topic as well as to the possible applications in molecular switches and other organic electronics. Nevertheless, very few reports have been published on SAMO states of larger fullerenes so far. Using density functional theory, we attempt to partially remedy this situation by presenting a study on SAMO states in C(82 )and its Ca and Sc endohedrally doped derivatives, comparing results with previous relevant findings for C-60. We find that C-82 possesses higher SAMO energies compared to C-60, as associated with the symmetry of the molecule, and that endohedral doping leads to energetically favorable side positions of Ca and Sc inside the C-82 cage. Among the two, Sc@C-82 has more stable SAMO states compared to Ca@C(82 )as reflected by the shift in the density of states, while the charge states are found to be similar. In the case of the monolayer form, the p z - and 2s-SAMO orbitals overlap with the nearest neighbors, causing parabolic band dispersion with the formation of near free electron states and that the SAMO state energies move closer to the Fermi energy compared to the related molecules. These findings provide promising information about the distribution of SAMO states in C-82 fullerene, which can be further relevant in studies of SAMO states of higher fullerenes and for coming applications of these systems.