  A model has been developed that illustrates the emergence of C60 from the
condensing carbon vapor. It is shown to depend upon the decreasing heats of
formation for larger cages, exponentially increasing number of isomers for
fullerenes that are larger than C60, large cages buckling induced by the
pentagon-related protrusions that initiate fragmentation, the structural
instability induces fragmentation that shrinks large cages and an evolving gas
of C2 that is crucial to the whole process. The model describes a mechanism for
the provision and presence of plenty of C2 during the formation and
fragmentation processes. The bottom-up formations of large cages followed by
the top-down cage shrinkage are shown to be stable, dynamical processes that
lead to the C60 dominated fullerene ensemble.
