Differential Scattering Cross-Sections for the Different Product Vibrational States in the Ion-Molecule Reaction Ar+ + N2

TL;DR

This study measures how different vibrational states are produced in the Ar+ + N2 reaction, revealing energy-dependent scattering patterns that improve understanding of ion-molecule interactions.

Contribution

It provides detailed three-dimensional velocity map imaging data of vibrational state-specific scattering in the Ar+ + N2 reaction, advancing the quantitative understanding of this fundamental process.

Findings

Vibrational excitation dominates in forward scattering.

Higher vibrational states are observed at larger angles.

Lower collision energies favor higher scattering angles.

Abstract

The charge transfer reaction Ar+ + N2 --> Ar + N2+ has been investigated in a crossed beam experiment in combination with three-dimensional velocity map imaging. Angular differential state-to-state cross sections were determined as a function of the collision energy. We found that scattering into the first excited vibrational level dominates as expected, but only for scattering in the forward direction. Higher vibrational excitations up to v'=6 have been observed for larger scattering angles. For decreasing collision energy, scattering into higher scattering angles becomes increasingly important for all kinematically allowed quantum states. Our detailed measurements indicate that a quantitative agreement between experiment and theory for this basic ion-molecule reaction now comes within reach.