https://doi.org/10.1140/epjd/e2017-80062-5
Regular Article
Collision-induced evaporation of water clusters and contribution of momentum transfer*
1 LiPhy, University Grenoble-Alpes and CNRS, UMR 5588, 140 Av. de la Physique, 38402 St Martin d’ Hères, France
2 Université de Lyon, 69003 Lyon, France
3 Université Lyon 1, 69100 Villeurbanne, France
4 Institut de Physique Nucléaire de Lyon, CNRS/IN2P3 UMR 5822, Domaine Scientifique de la Doua, Batiment Paul Dirac, 4 rue Enrico Fermi, 69622 Villeurbanne Cedex, France
a
e-mail: florent.calvo@univ-grenoble-alpes.fr
Received: 30 January 2017
Received in final form: 3 March 2017
Published online: 18 May 2017
The evaporation of water molecules from high-velocity argon atoms impinging on protonated water clusters has been computationally investigated using molecular dynamics simulations with the reactive OSS2 potential to model water clusters and the ZBL pair potential to represent their interaction with the projectile. Swarms of trajectories and an event-by-event analysis reveal the conditions under which a specific number of molecular evaporation events is found one nanosecond after impact, thereby excluding direct knockout events from the analysis. These simulations provide velocity distributions that exhibit two main features, with a major statistical component arising from a global redistribution of the collision energy into intermolecular degrees of freedom, and another minor but non-ergodic feature at high velocities. The latter feature is produced by direct impacts on the peripheral water molecules and reflects a more complete momentum transfer. These two components are consistent with recent experimental measurements and confirm that electronic processes are not explicitly needed to explain the observed non-ergodic behavior.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2017
