Combined topological and energy analysis of the annealing process in fullerene formation. Stone-Wales interconversion pathways among IPR isomers of higher fullerenes

An algorithm for finding all the possible products from consecutive generalized stone-Wales (GSW) rearrangements of any fullerene or closed cage precursor has been developed. Combined with energy-minimization, the program provides a versatile tool for the analysis of extremely complex interconversion pathways in the annealing process of fullerene formation. This paper presents results of the following preliminary applications of the program: (1) identification of the shortest pathway from Wang's C(60) cage precursor to [60-I(h)]fullerene, (2) availability of GSW cascades for a large number of sixty-carbon cage precursors leading to [60-I(h)]fullerene, (3) generation of interconversion pathways among IPR isomers of higher [n]fullerenes (n = 78, 80, 82, 84, 90), and (4) enumeration of fullerene isomers, The pathways map of [84]fullerene solved the pending problem of why the high-energy isomer, [84-D(2d)(I)]fullerene, has been detected using a helium-labelling technique in the product mixture and confirmed by IGOR calculation: this particular isomer is the dead-end product of a downhill bypath.