LiHe$^+$ in the early Universe: a full assessment of its reaction network and final abundances

TL;DR

This study uses ab initio quantum calculations to determine reaction rates and model the evolution of LiHe$^+$ abundance in the early Universe, providing insights into its chemical role during cosmic dawn.

Contribution

It offers the first comprehensive reaction network and abundance predictions for LiHe$^+$ in the early Universe based on ab initio quantum calculations.

Findings

Derived accurate reaction rates for LiHe$^+$ processes.

Predicted the evolution of LiHe$^+$ abundance over redshift.

Compared LiHe$^+$ abundance with other polar cations in the early Universe.

Abstract

We present the results of quantum calculations based on entirely ab initio methods for a variety of molecular processes and chemical reactions involving the LiHe$^+$ ionic polar molecule. With the aid of these calculations we derive accurate reaction rates and fitting expressions valid over a range of gas temperatures representative of the typical conditions of the pregalactic gas. With the help of a full chemical network, we then compute the evolution of the abundance of LiHe$^+$ as function of redshift in the early Universe. Finally, we compare the relative abundance of LiHe$^+$ with that of other polar cations formed in the same redshift interval.