Unified treatment of resonant and non-resonant mechanisms in dissociative recombination: benchmark study of CH$^+$

TL;DR

This paper introduces a unified theoretical approach for modeling dissociative recombination in diatomic ions, successfully applied to CH$^+$, and validated against experimental data, simplifying calculations by avoiding separate evaluations of couplings.

Contribution

The paper presents a novel, unified theoretical framework for dissociative recombination that simplifies calculations and applies to molecules with or without electronic resonances.

Findings

The approach accurately predicts the DR cross section for CH$^+$.

Computed cross sections agree well with cryogenic storage-ring experimental data.

The method simplifies the calculation process by not requiring separate coupling evaluations.

Abstract

The theoretical approach developed here treats uniformly the direct and indirect mechanisms of dissociative recombination (DR) in a diatomic ion. The present theory is based on electron scattering calculations performed at several internuclear distances in the molecule. It is easy to implement becaus there is no need to separately evaluate couplings and the bound dissociative states of the neutral molecule. The theory can be applied to molecular ions with or without electronic resonances at low energies. The approach is applied to compute the DR cross section in electron-CH$^+$ collisions. The computed cross section agrees generally well with recent state-resolved data from a cryogenic storage-ring experiment, which validates the approach.