Extended Data Fig. 7: MD simulation of fcc-C60 heated to different temperatures at 30 GPa.
a, Classic MD simulation of fcc-C60, heating rate: 1010 K/s. The fraction of sp3 bonds increase with increasing temperature. There is a percolation transition of sp3 bonds at 500-800 K. Such a percolation transition corresponds to the polymerization of C60 molecules. It should be pointed out that the fractions of sp3 bonding were determined based on the criterion of 4-fold bonding within 1.85 Å, which may slightly underestimate the real sp3 fraction of the sample by a few percent. b, Ab initio MD simulation of fcc-C60 (720 atoms), heating rate: 2 × 1014 K/s. Similar to classic MD simulation, the fraction of sp3 bonds increases with increasing temperature in ab initio MD. The simulation results validate what was observed in classical MD. Note the persistence of parallel sp3 bonds at 900 K and 1200 K.
