Ab initio study of dititanium endofullerenes: D5d- and D5h-Ti2@C80

Theoretical ab initio studies of the structure and electronic properties of two dititanium endofullerene isomers Ti2@C80 with D5d and D5h symmetry were carried out. For each configuration, optimized atomic structures were obtained using RHF-level (STO-3G∗ basis) calculations. The electronic structure and atomic charges of endofullerenes were computed by the DFT method in the discrete variation approach. The results were analyzed in comparison with “empty” D5d-, D5h-C80 fullerenes. The obtained charge density maps show that the valence states of Ti atoms in D5h-Ti2@C80 overlap with those of the C80 cage indicating the existence of covalent bonding between titanium and the carbon cage. The atomic charge of each Ti atom inside the C80 cage is equal to +1.9 e providing a formal ionic state of the dititanium endofullerene (Ti2+)2@C804+.