Influence of a quasi-molecular mechanism of recombination on the formation of hydrogen in the early universe

TL;DR

This paper investigates how a quasi-molecular mechanism influences hydrogen formation during the early universe's recombination era, highlighting the role of $H_2^+$ and the impact of a second proton on recombination rates.

Contribution

It introduces a quantitative analysis of hydrogen formation via a quasi-molecular approach, emphasizing the formation of $H_2^+$ and the effects of a second proton on recombination dynamics.

Findings

Formation of $H_2^+$ is comparable to atomic hydrogen creation.

Participation of a second proton increases electron binding energy.

The quasi-molecular mechanism affects recombination rates.

Abstract

In the framework of a quasi-molecular approach, the formation of hydrogen atom in the pre-recombination period of evolution of the universe is analysed quantitatively. Calculations in an adiabatic multi-level representation enable estimates of probabilities of radiative transitions. The quasi-molecular mechanism of recombination allows the formation of hydrogen molecular ion, $H_2^+$, in its ground state. The probability of this process is comparable with the probability of the creation of atomic hydrogen. The participation of a second proton in the recombination increases the binding energy of an electron and decreases the rate of recombination of hydrogen.