RESONANT FREE-ELECTRON CAPTURE SPECTRA OF C60F48

Resonant electron capture spectra of C60F48 and its oxy-analogue C60F4 8O have been studied and interpreted. Long-lived parent negative ions are formed within a 0-8 eV energy range with a maximum yield at approx imately 0.14 eV. Going from thermal energy and up to 8 eV, these paren t anions undergo fragmentation with generation of even-numbered fluori ne negative ions due to sequential loss of F-2 down to C60F36- and C60 F36O-, respectively; the yield of fragment anions at thermal energy ri ses with the degree of fragmentation. At approximately 8 eV and above, the odd-numbered fluorine fragment anions were registered, The format ion of these anions in the energy range 17-45 eV was associated with t he resonant state where the excitation of a-plasmons is supposed to oc cur. The appearance energies of positive parent and fragment ions from C60F48 as well as parent C60F36+ have been measured. The parent ion C 60F48- undergoes electron autodetachment at 3-4 eV with a mean lifetim e in the millisecond scale. Estimations for C-F bond dissociation ener gy and electron affinity of C60F47 are reported. Published by Elsevier Science B.V.