Rotational transitions induced by collisions of HD$^{+}$ ions with low energy electrons

TL;DR

This study uses Multichannel Quantum Defect Theory to compute cross sections and rate coefficients for rotational transitions and dissociative recombination of HD$^+$ ions colliding with electrons, aligning well with experimental data.

Contribution

It provides the first comprehensive rotational transition and dissociative recombination cross sections for HD$^+$ ions with electrons using MQDT, improving accuracy over previous models.

Findings

Good agreement with previous theoretical and experimental results.

Enhanced accuracy of dissociative recombination cross sections.

Provided rate coefficients for a range of temperatures.

Abstract

A series of Multichannel Quantum Defect Theory-based computations have been performed, in order to produce the cross sections of rotational transitions (excitations $N_{i}^{+}-2 \rightarrow$ $N_{i}^{+}$, de-excitations $N_{i}^{+}$ $\rightarrow$ $N_{i}^{+}-2$, with $N_{i}^{+}=2$ to $10$) and of their competitive process, the dissociative recombination, induced by collisions of HD$^+$ ions with electrons in the energy range $10^{-5}$ to 0.3 eV. Maxwell anisotropic rate coefficients, obtained from these cross sections in the conditions of the Heidelberg Test Storage Ring (TSR) experiments ($k_{B}T_{t}=2.8$ meV and $k_{B}T_{l}=45$ $\mu$eV), have been reported for those processes in the same electronic energy range. Maxwell isotropic rate coefficients have been as well presented for electronic temperatures up to a few hundreds of Kelvins. Very good overall agreement is found between our results for rotational transitions and the former theoretical computations as well as with experiment. Furthermore, owing to the full rotational computations performed, the accuracy of the resulting dissociative recombination cross sections is considerably improved.