# Molecular Hydrogen: a benchmark system for Near Threshold Resonances at higher partial waves

## TL;DR

This paper investigates how Near Threshold Resonances influence scattering processes in molecular hydrogen systems, revealing unique energy scaling behaviors for higher partial waves through theoretical analysis and modeling.

## Contribution

It provides a detailed theoretical analysis of NTR effects on higher partial wave scattering in H2-based systems using a three-channel model and Jost functions.

## Key findings

- NTRs alter the energy scaling of scattering cross sections.
- Higher partial waves exhibit distinct NTR effects compared to s-wave.
- Long-range potential effects are discussed.

## Abstract

Benchmark reactions involving molecular hydrogen, such as H$_2$+D or H$_2$+Cl, provide the ideal platforms to investigate the effect of Near Threshold Resonances (NTR) on scattering processes. Due to the small reduced mass of those systems, shape resonances due to particular partial waves can provide features at scattering energies up to a few Kelvins, reachable in recent experiments. We explore the effect of NTRs on elastic and inelastic scattering for higher partial waves $\ell$ in the case of H$_2$+Cl for $s$-wave and H$_2$+D for $p$-wave scattering, and find that NTRs lead to a different energy scaling of the cross sections as compared to the well known Wigner threshold regime. We give a theoretical analysis based on Jost functions for short range interaction potentials. To explore higher partial waves, we adopt a three channel model that incorporates all key ingredients, and explore how the NTR scaling is affected by $\ell$. A short discussion on the effect of the long-range form of the interaction potential is also provided.