Potential energy fullerene formation

FIG. 3 Planar monocyclic, bicycllc and tricyclic C40 ions form fullerene plus C2 when collisionally heated above the isomerization barrier for fullerene formation (see Fig. 2b). All structures shown are minima on the potential energy surface, according to semi-empirical PM3 electronic structure calculations. The bicycllc and tricyclic rings have lower isomerization barriers to fullerene formation than the monocyclic ring. 

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