Studies of fragmentation of multi-charged C60r+ produced in slow highly charged ion-fullerene collisions

par Baoren Wei

Thèse de doctorat en Physique

Sous la direction de Serge Martin et de Xinwen Ma.

Soutenue en 2005

à Lyon 1 en cotutelle avec l'Académie des Sciences, Lanzhou (Chine) .

mots clés

• Fullerènes
• Collisions (physique)
• Ions multichargés

Pas de résumé disponible.

Résumé

The stability and fraglmentation of C60r+ in three excitation energy regimes have been studied in this work. Stable C60r+ produced via charge exchange mechanism in collisions of 56 keV Ar8+-C60 were stored in a compact electrostatic Cone Trap developed at University Lyon 1. The experimental results show that the lifetime limit of C60r+ (r = 2~5) is very large, larger than 400 ms. Decay of C60r+ at low internal energy in a time range of 20 [mu]s by evaporation of a C2 unit was also studied. With a statistical model taken into account of the radiative decay process, the distribution of excitation energy was obtained. C60r+ at higher internal energies due to primary electronic energy deposition were produced in frontal collisions with He+ at 7 ~ 20 keV. A parent intial charge differentiated TOF spectroscopy technique has been employed to study the ionization of the C60 as e fuction of the collision velocity. The fragmentation pattern was found to depend only on the inital charge state of the parent ions C60r+ but independent of the collision velocity