We report results of a survey of the energetics and stability of classical and 1-heptagon nonclassical fullerene clusters in the range of sizes ${\mathrm{C}}_{30}$ to ${\mathrm{C}}_{70},$ using both total-energy tight-binding and first-principles density functional theory methods. We conclude from this survey that 1-heptagon isomers of high stability exist at every nuclearity, and that these nonclassical isomers play an important part in the growth mechanism of fullerenes.

• Received 22 January 2001

DOI:https://doi.org/10.1103/PhysRevB.63.193403