Charged-Particle-Induced Molecular Fragmentation at Large Velocities

Abstract

A present major challenge is the understanding of molecular-fragmentation dynamics. Numerous studies have already been devoted to molecular fragmentation induced either by electron impact (see, for example, [1] for a review), synchrotron radiation ([2–4] or [5] for a review), or femtosecond lasers [6] . Some very first studies using fast multicharged ions have been reported 7–10] . In the case of ion-induced fragmentation, one may address many different fundamental aspects. On the one hand, the study of the fragmentation may be used as a probe of the electronic processes involved. In the field of radiation damage, these processes dominantly contribute to energy loss of swift projectiles in matter. Indeed, the energy is deposited on the electrons [11] and is known to lead to the production of defects due to displacement of atoms. One fundamental remaining question in this field is how electronic energy is transformed into kinetic energy of the nuclei, which finally ends as tracks in the bulk. Ion-impact-induced fragmentation of molecules is an example of how this transfer may proceed. In the particular case of biological tissue, water radiolysis is identified as an important effect leading to the observed damages (cell death or mutation) [12] . The study of the fragmentation of H₂O is therefore important for that issue [13,14].