Berlin 2001 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
A: Atomphysik
A 12: Posters Thursday (Ion/Atom/Molecule/Surface Scattering)
A 12.25: Poster
Donnerstag, 5. April 2001, 12:30–15:00, AT3
Coulomb-fragmentation of O2 in collisions with Xe18+ and Xe43+ at 5.9 MeV/u — •I. Küster1, B. Siegmann1, U. Werner1, N.M. Kabachnik1, H.O. Lutz1, and R. Mann2 — 1Fakultät für Physik, Universität Bielefeld, 33615 Bielefeld — 2Gesellschaft für Schwerionenforschung (GSI), 64291 Darmstadt
The multiple ionization and fragmentation of O2 by fast Xe18+ and Xe43+ ions was studied utilizing a position and time-sensitive multiparticle detector. The experiment has been performed using the highly charged ion beam of the UNILAC accelerator at the GSI Darmstadt. The slow Oq+ ions and electrons generated in the collision process are separated by a homogeneous electric field. Correlated fragment ions are detected in coincidence by the time- and position-sensitive multi-particle detector which is triggered by an electron registered by a channeltron. Of special interest are the “Coulomb explosion” processes O2 —→ Oq+ + Op+. If both fragments are detected, a kinematically complete study of the molecular break-up process is possible, and the dissociation energy as well as the orientation of the molecular axis can be derived for each individual event. The results of this analysis show that the most probable kinetic energy release is described approximately by a point-charge Coulomb explosion (CE) model; the width of the distributions, however, is much larger than predicted by the CE model. For higher fragment charge states the position of the maximum as well as the width of the kinetic energy release spectra are satisfactorily described by a recently suggested more elaborate CE model based on a statistical description of the individual states of the intermediate molecular ion.