Molecular fluorine chemistry in the early Universe

TL;DR

This paper models fluorine chemistry in the early Universe, predicting the formation of HF molecules during the dark age, which could influence cosmic microwave background anisotropies and proto-object evolution.

Contribution

It provides the first comprehensive chemical model of fluorine in the early Universe, including abundance calculations of F, F-, and HF as functions of redshift.

Findings

HF molecules could form during the dark age of the Universe.

Predicted HF abundance is approximately 3.75×10^(-17) for initial fluorine abundance of 10^(-15).

Fluorine hydrides may impact cosmic microwave background observations.

Abstract

Some models of Big Bang nucleosynthesis suggest that very high baryon density regions were formed in the early Universe, and generated the production of heavy elements other than lithium such as fluorine F. We present a comprehensive chemistry of fluorine in the post-recombination epoch. Calculation of F, F- and HF abundances, as a function of redshift z, are carried out. The main result is that the chemical conditions in the early Universe can lead to the formation of HF. The final abundance of the diatomic molecule HF is predicted to be close to 3.75 10(-17) when the initial abundance of neutral fluorine F is 10(-15). These results indicate that molecules of fluorine HF were already present during the dark age. This could have implications on the evolution of proto-objects and on the anisotropies of cosmic microwave background radiation. Hydride of fluorine HF may affect enhancement of the emission line intensity from the proto-objects and could produce spectral-spatial fluctuations.