Benchmarking an improved statistical adiabatic channel model for competing inelastic and reactive processes

Abstract

Inelastic collisions and elementary chemical reactions proceeding through the formation and subsequent decay of an intermediate collision complex, with an associated deep well on the potential energy surface, pose a challenge for accurate fully quantum mechanical approaches, such as the close-coupling method. In this study, we report on the theoretical prediction of temperature-dependent state-to-state rate coefficients for these complex-mode processes, using a statistical quantum method. This statistical adiabatic channel model is benchmarked by a direct comparison using accurate rate coefficients from the literature for a number of systems (H2 + H+, HD + H+, SH+ + H, and CH+ + H) of interest in astrochemistry and astrophysics. For all of the systems considered, an error of less than factor 2 was found, at least for the dominant transitions and at low temperatures, which is sufficiently accurate for applications in the above mentioned disciplines.

11 pages, 5 figures

References in corpus (6)

• An efficient statistical method to compute molecular collisional rate coefficients
• Formation of interstellar SH${}^{+}$ from vibrationally excited H${}_2$: Quantum study of S${}^{+}$ + H${}_2$ $\rightleftarrows$ SH${}^{+}$ + H reactions and inelastic collisions
• The effect of CO-H2O collisions in the rotational excitation of cometary CO
• Hyperfine excitation of SH${}^{+}$ by H
• Experimental and Theoretical Studies of the N(2D) + H2 and D2 Reactions
• Quantum mechanical study of the high-temperature ${\mathrm{H}}^{+}+\mathrm{HD}\to {\mathrm{D}}^{+}+{\mathrm{H}}_2$ reaction for the primordial universe chemistry

Cited by in corpus (3)

• The effect of water and electron collisions in the rotational excitation of HF in comets
• Spin-orbit transitions in the N${}^{+}$(${}^3{P}_{J_A}$) + H${}_2$ $\to$ NH${}^{+}$($X^2\Pi$, ${}^4{\Sigma }^{-}$)+ H(${}^{2}S$) reaction, using adiabatic and mixed quantum-adiabatic statistical approaches
• Gas phase Elemental abundances in Molecular cloudS (GEMS) VIII. Unlocking the CS chemistry: the CH + S$\to$ CS + H and C${}_2$ + S$\to$ CS + C reactions