Towards formation of buckminsterfullerene C_60 in quantum chemical molecular dynamics

摘要

We present follow-up studies on the formation mechanism of fullerene molecules from random ensembles of C_2 molecules using quantum chemical molecular dynamics.Two possible roadmaps are investigated as to how buckminsterfullerene C_60 and higher fullerenes could be formed.In a "size-up" scenario,fullerenes of the cage size of C_72-C_96 were found to form directly from high concentrations of C_2 molecules at 2000 K with periodic supply of batches of additional C_2's.In a "size-down" approach,smaller fullerenes are sometimes formed by losing carbon fragments in "fall-off" or "pop-out" annealing processes under prolonged heating of giant fullerenes,which were self-assembled at initial stages from C_2's with lower concentrations.Both roadmaps are found to provide explanations for the appearance of C_60 and larger fullerenes in combustion and carbon arc experiments.