Fullerene Dimers: Cohesive Energy, Electronic Structure, and Vibrational Modes

To address experiments suggesting the polymerization of ${\mathrm{C}}_{60}$, via four-membered rings, we have performed density-functional-based calculations on a [${\mathrm{C}}_{60}$${]}_2$ dimer. The dimer is bound with respect to the isolated molecules, has a short center-to-center separation, and vibrational signature that is similar to what is observed experimentally.