Recent Results on Multiple Ionization and Fragmentation of Negatively Charged Fullerene Ions by Electron Impact
Abstract
Employing the dynamic crossed-beams technique, the absolute cross sections of the electron-impact multiple ionization and fragmentation of mass-selected negatively charged fullerene ions Cm‑ → Cm‑n2+ (m=60, 70, 84; q=1, 2, 3; n=0, 2, 4) were measured. The electron energy varied from the respective threshold up to 1 keV. A scaling law was observed for the cross-section magnitude as a function of the fullerene size m and the charge state q of product ions. The data indicate that different mechanisms account for the detachment of an extra electron from the negatively charged fullerene and the formation of a positively charged ion, respectively. Moreover, the multiple ionization of a fullerene anion is found to be a sequential process. A novel ionization mechanism is proposed which might be expected to be valid for all negatively charged molecular or cluster ions able to shield the attached electron from the incident electron.
- Publication:
-
Physics of the Solid State
- Pub Date:
- March 2002
- DOI:
- 10.1134/1.1462690
- Bibcode:
- 2002PhSS...44..511H
- Keywords:
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- Spectroscopy;
- Fullerene;
- Electron Energy;
- Charge State;
- Recent Result