Rate equations were proposed for the generation and recombination of vacancies and self-interstitial atoms in a spherical bucky onion under electron irradiation. These were used to study the temporal development of the point defect concentrations in various onions shells. The self-interstitial concentration was found to remain low, and to be only slightly enriched near to the onion's center. The loss of atoms from the outer surface of the bucky onions, via sputtering, acted as a vacancy source for the whole onion. Irradiation-induced diffusion led to a net migration of vacancies towards the onion core. The coupling, between neighboring shells, which was necessary for such radial diffusion could be described by invoking an intermediate-shell concept.

W.Sigle, P.Redlich: Philosophical Magazine Letters, 1997, 76[3], 125-32