Formation of H${}_3^{-}$ by radiative association of H${}_2$ and H${}^{-}$ in the interstellar medium

Abstract

We develop the theory of radiative association of an atom and a diatomic molecule within a close-coupling framework. We apply it to the formation of H${}_3^{-}$ after the low energy collision (below 0.5 eV) of H${}_2$ with H${}^{-}$. Using recently obtained potential energy and permanent dipole moment surfaces of H${}_3^{-}$, we calculate the lowest rovibrational levels of the H${}_3^{-}$ electronic ground state, and the cross section for the formation of H${}_3^{-}$ by radiative association between H${}^{-}$ and ortho- and para-H${}_2$. We discuss the possibility for the H${}_3^{-}$ ion to be formed and observed in the cold and dense interstellar medium in an environment with a high ionization rate. Such an observation would be a probe for the presence of H${}^{-}$ in the interstellar medium.

References in corpus (2)

• Astronomical identification of CN-, the smallest observed molecular anion
• Detection of C5N- and vibrationally excited C6H in IRC +10216

Cited by in corpus (6)

• Tunneling in a very slow ion-molecule reaction
• Formation of molecular ions by radiative association of cold trapped atoms and ions
• New theoretical method for calculating the radiative association cross section of a triatomic molecule: Application to N2-H-
• A surface-hopping method for semiclassical calculations of cross sections for radiative association with electronic transitions
• Resonant states of H${}_3^{-}$ molecule and its isotopologues D${}_2$H${}^{-}$ and H${}_2$D${}^{-}$
• Radiative electron attachment to rotating C${}_3$N through dipole-bound states