Imaging resonances in low-energy NO-He inelastic collisions

TL;DR

This paper reports the first observation of scattering resonances in inelastic NO-He collisions, revealing detailed resonance structures and their partial wave composition through high-resolution experiments and quantum calculations.

Contribution

It presents the experimental detection of scattering resonances in differential cross sections for NO-He collisions and analyzes their partial wave contributions, a novel achievement in molecular collision studies.

Findings

Resonance fingerprints observed in differential cross sections.

Excellent agreement between experiment and quantum calculations.

Partial wave analysis reveals resonance evolution during collisions.

Abstract

In molecular collisions, resonances occur at specific energies where the colliding particles temporarily form quasi-bound complexes, resulting in rapid variations in the energy dependence of scattering cross sections. Experimentally, it has proven challenging to observe such scattering resonances, especially in differential cross sections. We report the observation of resonance fingerprints in the state-to-state differential cross sections for inelastic NO-He collisions in the 13 to 19 cm$^{-1}$ energy range with 0.3 cm$^{-1}$ resolution. The observed structures were in excellent agreement with quantum scattering calculations. They were analyzed by separating the resonance contributions to the differential cross sections from the background through a partitioning of the multichannel scattering matrix. This revealed the partial wave composition of the resonances, and their evolution during the collision.