Thermal Rate Coefficients for the Astrochemical Process C + CH${}^{+}$ $\to$ C${}_2^{+}$ + H by Ring Polymer Molecular Dynamics

Abstract

Thermal rate coefficients for the astrochemical reaction C + CH${}^{+}$ $\to$ C${}_2^{+}$ + H were computed in the temperature range 20-300 K by using novel rate theory based on ring polymer molecular dynamics (RPMD) on a recently published bond-order based potential energy surface and compared with previous Langevin capture model (LCM) and quasi-classical trajectory (QCT) calculations. Results show that there is a significant discrepancy between the RPMD rate coefficients and the previous theoretical results which can lead to overestimation of the rate coefficients for the title reaction by several orders of magnitude at very low temperatures. We argue that this can be attributed to a very challenging energy profile along the reaction coordinate for the title reaction, not taken into account in extenso by either the LCM or QCT approximation. In the absence of any rigorous quantum mechanical or experimental results, the computed RPMD rate coefficients represent state-of-the-art estimates to be included in astrochemical databases and kinetic networks.

References in corpus (5)

• The UMIST database for astrochemistry 2012
• A KInetic Database for Astrochemistry (KIDA)
• Reaction Networks For Interstellar Chemical Modelling: Improvements and Challenges
• Chemical Reaction Rates from Ring Polymer Molecular Dynamics: Theory and Practical Applications
• The CH+ Abundance in Turbulent, Diffuse Molecular Clouds

Cited by in corpus (3)

• Ring Polymer Molecular Dynamics and Active Learning of Moment Tensor Potential for Gas-Phase Barrierless Reactions: Application to S + H2
• The low temperature D${}^{+}$ + H${}_2$ $\to$ HD + H${}^{+}$ reaction rate coefficient: a ring polymer molecular dynamics and quasi-classical trajectory study
• Assessing Parameters for Ring Polymer Molecular Dynamics Simulations at Low Temperatures: DH+H Chemical Reaction