Resonant electron capture mass spectra of fullerenes C-60 and C-70

Resonant electron capture by C-60 and C-70 was studied and it was established that long-lived (i.e. mass spectrometrically observable) parent negative ions are formed within an extremely broad energy region (0-14 eV). It has been shown that effective yield curves of C-60(-) and C-70(-) in the thermal energy region have resonant peaks at 0.05 +/- 0.01 and 0.06 +/- 0.01 eV, respectively. Owing to the higher energy resolution than in previously published experiments, it was possible to observe another resonant state at ca. 0 eV for both fullerenes (as a shoulder on the effective yield curve). This gives evidence of the possibility of s-electron attachment by the fullerenes. A correlation between electron capture, electron loss energy and photoelectron spectra was found. At 6.5 eV and above, C-60(-) and C-70(-) are subject to electron autodetachment and mean lifetime and mean decay rates were directly measured. (C) 1997 by John Wiley & Sons, Ltd.