First CPMD Study on Fe-catalyzed SWNT Growth: J.-Y. Raty, F. Gygi, and G. Galli, Phys. Rev. Lett. 95, 096193 (8/26/05)
initial structure
snapshots after adding C atoms, 10 ps
F. Ding, A. Rosén, and K. Bolton,  J. Phys. Chem. B, 108, 17369-17377 (2004).
Reminder:
Again, QM/MD is ~ 1000 times faster than MM/MD!
Enormous computational effort!