Prediction of favorable isomeric structures for the C100 to C120 giant fullerenes. An application of the phason line criteria

The phason line criteria that we have developed to exclude unstable isomers of fullerenes that satisfy the isolated pentagon rule (IPR) was applied to predict stable isomeric structures of eleven giant fullerenes Cn (n = 100 to 120).A total of 4868 zero-node and no-phason line (leapfrogs) structures were first screened out from a total of 39 621 IPR isomers generated for these fullerenes.They were then subjected to MM3 geometry optimization.The best ten structures for each fullerene family thus obtained were further geometry-optimized with the semiempirical MO method, AM1/MOPAC.We find that C100 represents a borderline case between the higher fullerenes (76 ≤ n ≤ 100) in which the skeletal strain greatly influences the stability and the giant fullerenes (n ≥ 100) in which π-electron configuration dominates the stability.The well-studied T d -C120 leapfrog isomer was reconfirmed to be outstandingly stable.