Benchmarking an improved statistical adiabatic channel model for competing inelastic and reactive processes
Résumé
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. © 2021 Author(s).
Mots clés
Astrophysics
Potential energy
Quantum chemistry
Reaction intermediates
Close-coupling method
Elementary chemical reaction
Inelastic collision
Quantum mechanical
Rate coefficients
Reactive process
Statistical adiabatic channel models
Temperature dependent
Potential energy surfaces
Molecular physics
Quantum dynamics
Atomic and molecular collisions