Site occupancy and molecular complex formation of F-19 ions in fullerenes C-60 and C-70 studied by TDPAD

TDPAD spectroscopy measurements have been performed on two fullerene sample s, C-60 and C-70, with recoil implanted F-19 ions as probe nuclei. Quadrupo le coupling frequencies of nu(Q) = 54(1) MHz for C-60 and nu(Q) = 57(1) MHz for C-70 were observed. These frequencies are associated with a C-F molecu lar complex formation. The C-70 sample was also examined for possible effec ts due to variation of temperature. No significant changes were observed. A n additional frequency of nu(Q) = 13(1) MHz registered for both samples has to be attributed to the formation of H-F complexes. Finally, both samples were analysed for proton dose dependent effects, due to the (p, p'gamma) im plantation process but no effects have shown up. Specifically, computationa l studies based on quantum chemical methods were performed to assist in the interpretation of the experimental results, using the code MOPAC.