State selective study of H3+recombination in Cryo-FALP and SA-CRDS experiments at 77 K

Juraj Glosík,Petr Dohnal,Radek Plašil,Peter Rubovič,Michal Hejduk,Ábel Kálosi

doi:10.1051/epjconf/20158401002

Abstract

Rate coefficients for nuclear spin state-specific recombination of H + ions with thermal electrons were measured using FALP and SA techniques at temperatures 77-300K. For this purpose H2 gas with both thermal and enriched population of the para nuclear spin configuration was used. Measurements have shown that at 77K para-H + exhibits five times higher binary recombination rate coefficient than ortho-H + : (1.5 ± 0.4) × 10 −7 vs. (3 ± 2) × 10 −8 cm 3 s −1 .

Highlights

H+3 ion is the most abundantly produced molecular ion in interstellar space [1] and as such stands at the beginnings of astrochemical chains leading to formation of other astrophysically important molecules.One of its major destruction mechanisms, recombination with electronsH+3 + e− −→ bin−TDE(T ) H2 + H, H + H + H,(1a) where bin−TDE(T ) is recombination rate coefficients of H+3 ions with population of states according to thermal equilibrium at temperature T, has been studied for more than 60 years [2,3,4]
H+3 + e− −→ bin−TDE(T ) H2 + H, H + H + H, (1a) where bin−TDE(T ) is recombination rate coefficients of H+3 ions with population of states according to thermal equilibrium at temperature T, has been studied for more than 60 years [2,3,4]
Attention has been focused on the dependence of the recombination rate coefficient of H+3 ions on nuclear spin states of these ions: pH+3

Summary

Introduction

H+3 ion is the most abundantly produced molecular ion in interstellar space [1] and as such stands at the beginnings of astrochemical chains leading to formation of other astrophysically important molecules.One of its major destruction mechanisms, recombination with electronsH+3 + e− −→ bin−TDE(T ) H2 + H, H + H + H,(1a) where bin−TDE(T ) is recombination rate coefficients of H+3 ions with population of states according to thermal equilibrium at temperature T , has been studied for more than 60 years [2,3,4]. H+3 + e− −→ bin−TDE(T ) H2 + H, H + H + H, (1a) where bin−TDE(T ) is recombination rate coefficients of H+3 ions with population of states according to thermal equilibrium at temperature T , has been studied for more than 60 years [2,3,4]. The state-specific binary recombination has been studied by monitoring decay of the low temperature H+3 dominated afterglow plasma (in He/Ar/H2 gas mixture) [5,6,7] and by several storage ring experiments, see Refs.

Results

Conclusion