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Dynamique de la fragmentation de molécules simples induite par impacte d'ion multichargé

Abstract : The aim of this work is to study the dynamics of swift multicharged ion-induced fragmentation of diatomic (CO) and triatomic (CO2) molecules. Performed at the GANIL facility, this study used the Recoil Ion Momentum Spectroscopy technique (RIMS), which consists of time-of-flight mass spectrometer, coupled with a multi-hit capability position sensitive detector (delay line anode). The high-resolution measurement of the kinetic energy distribution released (KER) during the CO fragmentation points out the limitation of the Coulomb Explosion Model, revealing, for example, the dication CO2+ electronic state contribution in the case of C+/O+ fragmentation pathway. Furthermore, the multi-ionization cross section dependence with the orientation of the internuclear axis of CO is compared with a geometrical model calculation. Finally, different behaviours are observed for the dissociation dynamics of a triatomic molecule (CO2). While triple ionization leads mainly to a synchronous concerted fragmentation dynamics, a weak fraction of dissociating molecule follows a sequential dynamics involving CO2+ metastable states. In the case of double ionization, (CO2)2+ dication dissociation dynamics is asynchronous concerted and has been interpreted using a simple model involving an asymmetrical vibration of the molecule.
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https://tel.archives-ouvertes.fr/tel-00005217
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Submitted on : Friday, March 5, 2004 - 11:35:39 AM
Last modification on : Friday, June 28, 2019 - 1:47:20 AM
Long-term archiving on: : Friday, April 2, 2010 - 9:00:15 PM

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  • HAL Id : tel-00005217, version 1

Citation

Medhi Tarisien. Dynamique de la fragmentation de molécules simples induite par impacte d'ion multichargé. Physique Atomique [physics.atom-ph]. Université de Caen, 2003. Français. ⟨tel-00005217⟩

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