Fragmentation of water molecules in slow He2+ + H2O collisions
Résumé
The fragmentation in the collision system 3He2+ + H2O has been investigated experimentally at projectile energies ranging from 1 keV to 5 keV. The fragments were detected at angles from 25° to 130°. The experimental spectra exhibit two groups of peaks. The first one, which extends up to ~30 eV, is interpreted in terms of a Coulomb explosion mechanism. A second group observed at higher energies, corresponds to fragments and scattered projectiles produced in quasi-binary collisions. In the analysis, particular attention is paid to these energetic ions. Absolute cross sections dσ/dΩ, differential in the observation angle, are found to be in good agreement with calculations assuming that the interaction of the screened nuclei is described by the ZBL (Ziegler, Biersack and Littmark) potential.
Mots clés
Molecular fragmentation
Molecular dissociation
Molecular fragmentation dynamics
Fragment-energy distribution
Fragment-angular distribution
Electron capture
Ion-molecule collisions
Model calculations
Binary-encounter collisions
Elastic two-body collisions
Recoil ions
Scattering
Impact parameter
Coulomb explosion mechanism
ZBL potential