Formation and sputtering of fullerenes by MeV atomic ion

Abstract

Positive pure carbon cluster ions (C 2n + n from 20 to above 200) are ejected from solid films of poly(vinylidene-difluoride) when bombarded by MeV atomic ions. Similar results are obtained in the MeV ion interaction with a film of synthetic C 60F 2m ( m = 12–24) fullerenes. Measurements of the yield and the initial radial velocities of the ejected cluster ions are performed in a reflectron time-of flight mass spectrometer. Carbon cluster ions are formed and ejected as a result of a single MeV ion impact. The distribution of cluster sizes suggests that the clusters have closed carbon cage (fullerene) structure. Results on different types of coalescence reactions from synthetic C 60 fullerene targets and from blends of pure (synthetic) C 60 with a polystyrene polymer leading to ejection of higher mass positive fullerene ions (C m +, m from 60 to > 200) are reported. The coalescence reactions are also induced by the interaction of a single MeV ion with the solid. These experiments, providing information on the MeV ion-induced sputtering, may in its turn also contribute to the understanding of the fullerene formation mechanism in general.