Formation of the BeH+ and BeD+ Molecules in Be+ + H/D Collisions Through Radiative Association

Péter Szabó,Magnus Gustafsson,Szabolcs Góger

doi:10.3389/fspas.2021.704953

Abstract

Cross sections and rate coefficients for the formation of BeH+ and BeD+ molecules in Be+ + H/D collisions through radiative association are calculated using quantum mechanical perturbation theory and Breit-Wigner theory. The local thermodynamic equilibrium limit of the molecule formation is also studied, since the process is also relevant in environments with high-density and/or strong radiation fields. The obtained rate coefficients may facilitate the kinetic modelling of BeH+/BeD+ production in astrochemical environments as well as the corrosion chemistry of thermonuclear fusion reactors.

Highlights

Lithium, beryllium and boron are surprisingly rare in the Universe compared to other nuclides of similar mass, having abundances more similar to heavy nuclei in meteorites
Nonreactive processes may dominate in the collisions: bremsstrahlung under 10.0 eV and ionization and electronic excitation of the atoms above (Kramida et al, 2017)
We studied the radiative association formation of the BeH+ and BeD+ molecules

Summary

Introduction

Beryllium and boron are surprisingly rare in the Universe compared to other nuclides of similar mass, having abundances more similar to heavy nuclei in meteorites. The widely accepted explanation for this observation is that these elements cannot be produced in normal stellar nucleosynthesis while being depleted in hydrogen burning processes, producing helium (Burbidge et al, 1957). These elements can still be formed in spallation reactions of the more abundant elements e.g., carbon, nitrogen and oxygen. Out of these three elements, beryllium is the rarest, with a solar abundance of logεBe 1.15 ± 0.20 (with logεH 12.00 by definition) (Chmielewski and Müller, 1975). Later Shanmugavel et al (2008) gave an evidence for the presence of BeH and its isotopologues by observing their A-X transitions in sunspot umbral spectra

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