Structures and stabilities of directly-linked and oxygen-bridged fullerene dimers: A density-functional-theory study

The structures and the relative stabilities of the directly-linked fullerene dimer C₁₂₀ and of oxygen-bridged dimers of C₁₂₀O and C₁₂₀O₂ are systematically investigated via density-functionaltheory calculations. The structures of each dimer are identified as C₁₂₀(D_2h), C₁₂₀O(C_2v), and C₁₂₀O₂(C_2v(I)) by comparing the total energies of geometric isomers. From dissociation-energybarrier calculations, bridged dimers are more stable than directly-linked dimers. We find that the C₁₂₀ and the C₁₂₀O dimers will dissociate into two fullerene units while the C₁₂₀O₂ dimer remains at a certain energy range between 1.68 eV and 3.37 eV. Our theoretical results agree with the experimental data [J. Phys. Chem. B 110, 16979 (2006)].