ELECTRON-AFFINITIES OF HIGHER FULLERENES

Knudsen cell mass spectrometry has been used for the investigation of ion-molecule equilibria between gaseous neutral species and negative i ons in fullerene vapors at 800-900 K. Equilibrium constants of one-ele ctron exchange reactions between C60 and the higher fullerenes C70, C7 6, C78 and C84 have been measured. Electron affinities Of C70, C76, C7 8 and C84 were found to be 2.72 +/- 0.05, 2.88 +/- 0.05, 3.01 +/- 0.07 , and 3.05 +/- 0.08 eV, respectively. Negative ions of C86, C90, and C 92 were observed, and the lower limit of electron affinities for these species was estimated as greater-than-or-equal-to 3.0 eV.