Berlin 2001 – wissenschaftliches Programm
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A: Atomphysik
A 1: Posters Monday (Cluster, Atoms in Fields)
A 1.6: Poster
Montag, 2. April 2001, 12:30–15:00, AT3
Fast ion-impact on C60: multiple ionization, C2 evaporation, fission and multifragmentation — •A. Reinköster1, N.M. Kabachnik1,2, U. Werner1, and H.O. Lutz1 — 1Fakultät für Physik, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany — 2Institute of Nuclear Physics, Moscow State University, Moscow 119899, Russia
The multiple ionization and fragmentation of C60 have been studied in collisions with 50-300 keV·q H+, D+, He+, Ne+, and Arq+ (q=1-3) ions. Electrons and positive ions resulting from a collision are separated by a homogeneous electrical field and coincidences are recorded by a special multi-hit detector with position resolution and a negligible dead-time. The applied technique provides a deep insight into the complex fragmentation mechanisms of fullerene ions. Here, successive evaporation of neutral C2 units, super-asymmetric binary fissions of fullerene ions as well as C60 multifragmentation have been observed. The distributions of C60−2nq+ and Cn+ clusters show no strong dependence on the projectile velocity in the range under study. Furthermore, the kinetic energy release of fission processes (leading to C60−2nq++Cm+ coincidences, q=2-4, m,n=1-8) has been estimated. For the collision system H++C60 (v≥2 a.u.) cross sections and distributions of C60−2nq+ ions after C2 evaporations are comprehensible by a statistical model.