A Coulomb Over-the-Barrier Monte Carlo Simulation to probe Ion-Dimer Collision Dynamics

TL;DR

This study combines theoretical Coulomb Over-the-Barrier simulations with experimental COLTRIMS measurements to understand ion-dimer collision mechanisms, showing that dimers behave similarly to independent atoms during low-energy ion impacts.

Contribution

The paper introduces a simplified Coulomb Over-the-Barrier Model adapted for van der Waals dimers, validated against experimental data for collision dynamics.

Findings

Model predictions agree well with experimental results.

Van der Waals dimers behave similarly to independent atoms during collisions.

The approach effectively describes relaxation processes and momentum exchange.

Abstract

We present a combined theoretical and experimental study of primary and post-collision mechanisms involved when colliding low energy multiply charged ions with van der Waals dimers. The collision dynamics is investigated using a classical calculation based on the Coulombic Over-the- Barrier Model adapted to rare-gas dimer targets. Despite its simplicity, the model predictions are found in very good agreement with experimental results obtained using COLd Target Recoil Ion Momentum Spectroscopy (COLTRIMS), both for the relative yields of the different relaxation processes and for the associated transverse momentum exchange distributions between the projectile and the target. This agreement shows to which extent van der Waals dimers can be assimilated to independent atoms.