Atomic site sensitive processes in low energy ion-dimer collisions

TL;DR

This study investigates electron capture in low energy Ar9+ ion collisions with Ar2 dimers, revealing atom-specific interactions and charge sharing influenced by molecular orientation, supported by experimental data and Monte Carlo simulations.

Contribution

It provides new insights into atom-specific electron capture dynamics in ion-dimer collisions using combined experimental and classical modeling approaches.

Findings

Charge asymmetry in dissociation channels

Correlation between scattering angle and molecular orientation

Monte Carlo models match experimental charge sharing patterns

Abstract

Electron capture processes for low energy Ar9+ ions colliding on Ar2 dimer targets are investigated, focusing attention on charge sharing as a function of molecule orientation and impact parameter. A preference in charge-asymmetric dissociation channels is observed, with a strong correlation between the projectile scattering angle and the molecular ion orientation. The measurements provide here clear evidences that projectiles distinguish each atom in the target and, that electron capture from near-site atom is favored. Monte Carlo calculations based on the classical over-the-barrier model, with dimer targets represented as two independent atoms, are compared to the data. They give a new insight into the dynamics of the collision by providing, for the di erent electron capture channels, the two-dimensional probability maps p(~b), where ~b is the impact parameter vector in the molecular frame.