Associative detachment (AD) paths for H and CN- in the gas-phase: astrophysical implications

Abstract

The direct dynamical paths leading to Associative Detachment (AD) in the gas-phase, and specifically in the low-temperature regions of the Dark Molecular Clouds (DMC) in the ISM, or in cold trap laboratory experiments, are investigated with quantum chemical methods by using a high-level multi-reference Configuration Interaction (CI) approach that employs single and double excitations plus Davidson perturbative correction [MRSDCI(Q)] and the d-aug-cc-pV5Z basis set. The potential energy curves for H + CN- are constructed for different directions of the H partner approaching the CN- anion within the framework of the Born-Oppenheimer approximation. The present calculations found that the AD energetics at low temperature becomes favorable only along a selected range of approaching directions, thus showing that there is a preferred path of forming HCN at low temperatures, while that of forming its HNC isomer is found to be energetically forbidden. Given the existence in the ISM of different HCN/HNC ratios in different environments, we discuss the implications of our findings for selective formation of either isomer in the low-temperature conditions of the Molecular Cloud Cores.

References in corpus (7)

• HCN Survey of Normal Spiral, IR-luminous and Ultraluminous Galaxies
• Astronomical identification of CN-, the smallest observed molecular anion
• Comparative Chemistry of Diffuse Clouds II: CN, HCN, HNC, CH3CN & N2H+
• Nitrogen chemistry and depletion in starless cores
• Hydrogen Isocyanide in Comet 73P/Schwassmann-Wachmann (Fragment B)
• Gain-assisted superluminal light propagation through a Bose-Einstein condensate cavity system
• Associative Detachment of H$^{-$ + H $\to$ H${}_2$ + e${}^{-}$

Cited by in corpus (3)

• Associative detachment in anion-atom reactions involving a dipole-bound electron
• Cold reactive and non-reactive collisions of Li and Rb with C${}_2^{-}$: implications for hybrid trap experiments
• Vibrational Quenching of CN- in Collisions with He and Ar