Tomography of Feshbach Resonance States

TL;DR

This paper reports the detection and tomographic analysis of Feshbach resonances in cold collisions between molecular hydrogen ions and noble gases, revealing their unique signatures and non-statistical behavior.

Contribution

It introduces a novel experimental approach to detect and analyze Feshbach resonances in a benchmark molecular collision system using ion-electron coincidence detection.

Findings

Resolved all final molecular channels in a tomographic manner.

Demonstrated the non-statistical nature of the final state distribution.

Identified distinctive fingerprints of Feshbach resonance pathways in collision outcomes.

Abstract

Feshbach resonances are fundamental to interparticle interactions and become particularly important in cold collisions with atoms, ions, and molecules. Here we present the detection of Feshbach resonances in a benchmark system for strongly interacting and highly anisotropic collisions -- molecular hydrogen ions colliding with noble gas atoms. The collisions are launched by cold Penning ionization exclusively populating Feshbach resonances that span both short- and long-range parts of the interaction potential. We resolved all final molecular channels in a tomographic manner using ion-electron coincidence detection. We demonstrate the non-statistical nature of the final state distribution. By performing quantum scattering calculations on ab initio potential energy surfaces, we show that the isolation of the Feshbach resonance pathways reveals their distinctive fingerprints in the collision outcome.