First-Principles Determination of the Dispersion Interaction between Fullerenes and Their Intermolecular Potential

We compute, from first principles, the dispersion interaction between two and three fullerenes, in time-dependent density functional theory. These results, complemented with total energy calculations at small and intermediate distances, lead to a parameter-free determination of the interaction between fullerenes. Agreement with experiment, within 4%, is found for all quantities, computed via Monte Carlo simulations of fullerite. Inclusion of the three-body term is found to increase by 6% the cohesive energy at equilibrium density.