Berlin 2001 – wissenschaftliches Programm

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A: Atomphysik

A 7: Clusters II: Non-Metal Clusters, Fullerenes, Nanotubes (joint session A and MO)

A 7.4: Vortrag

Dienstag, 3. April 2001, 16:30–16:45, H1012

Collision-Induced Fragmentation of Argon Clusters — •Werner Tappe¹, Roman Flesch¹, Thomas Schlathölter², Ronnie Hoekstra², Reinhard Morgenstern², and Eckart Rühl¹ — ¹Fachbereich Physik, Universität Osnabrück, Barbarastr. 7, 49069 Osnabrück, Germany — ²Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen, The Netherlands.

Fragmentation of multiply charged argon clusters is investigated by multicoincidence spectroscopy. The experiments are carried out at an electron cyclotron resonance source at the KVI Groningen, where beams of Xe^Z+ (Z=5, 12, 17, 25) are produced. The ions are used as projectiles for collisions with free argon clusters after they are accelerated by 12 kV. Variable size argon clusters are prepared in a supersonic jet, where most experiments are performed at an average cluster size of 10. Ion-ion- and electron-ion-ion-coincidence spectra are recorded. Ar⁺/Arⁿ⁺ (n=1-7) coincidences are observed as a result of collisions with highly charged projectiles. Moreover, coincidences between singly charged atoms or clusters, such as Ar⁺/Ar₂⁺, are found preferentially in collisions with ions of lower charge, such as Xe^Z+ (Z≤ 5). Possible mechanisms of cluster fragmentation are discussed. The results are compared to earlier experiments on core-excited argon clusters.