On Atomistic and Coarse-Grained Models for C60 Fullerene.

Many atomistic and coarse-grained simulations of fullerene and fullerene derivatives are reported in the literature, but validation of both atomistic and coarse-grained models has been very limited. Here, we report a thorough validation of several all-atom fullerene models and refinement of the MARTINI coarse-grained (CG) fullerene model. The all-atom model by Girifalco had been parametrized using only solid-state properties (lattice constant, heat of sublimation), but it performs well also in the liquid state in terms of partitioning between different solvents. The new MARTINI CG model is optimized by matching experimental free energies of transfer between different solvents (for fullerene-solvent interactions) and atomistic fullerene-fullerene potentials of mean force (PMF) in water and in octane (for fullerene-fullerene interactions). The model gives reasonable results for solid-state properties and also reproduces atomistic results on the PMF in a lipid membrane. We conclude that the new MARTINI model is suitable for large-scale simulations of the interaction of fullerene with water, organic solvents, and lipid membranes.