Oxygen diffusion in solidC60: A molecular-dynamics calculation

We study the diffusion of ${\mathrm{O}}_2$ in crystalline ${\mathrm{C}}_{60}$ using a simplified model in which the ${\mathrm{C}}_{60}$ molecules are fixed at their equilibrium positions. We find that the jump frequencies of ${\mathrm{O}}_2$ molecules between octahedral sites of the cubic structures as a function of the molecular energy follow a simple potential law, calculate the diffusion coefficient for different values of the lattice parameter, and estimate the effect of orientational disorder of the host lattice. We discuss the available experimental evidence and estimate the C-O interaction energy at short distances.