Ion bombardment of C₆₀: Raman study of amorphization and polymerization

C₆₀ fullerite films on Si substrates have been bombarded with H, He, C and Ar ions with energies between 60 and 600 keV and doses ranging from 1 × 10¹² to 5 × 10¹⁶ cm^-2. Raman scattering showed structural changes of the fullerite depending on the ion species, energy and dose. At low doses a new line at 1463 cm^-1 in the Raman spectra indicates polymerization of C₆₀. At higher doses a broad and asymmetric line between 1000 and 1700 cm^-1 appears which is characteristic for amorphous carbon. The amorphization process is correlated with the nuclear energy deposition while electronic energy loss leads to polymerization of C₆₀.