Direct Chemical Dynamics Simulations of H₃⁺ + CO Bimolecular Reaction

Abstract

The proton transfer reaction H3 + + CO → HCO+/HOC+ + H2 has gained considerable attention in the literature due to its importance in interstellar chemistry. The reaction productsformyl cation (HCO+) and isoformyl cation (HOC+)are known to initiate multiple chemical reaction networks, resulting in complex molecules found in space. Several experimental and theoretical studies probing the structure and energetics of the [H3CO]+ system, HCO+/HOC+ product branching ratios, reaction mechanisms, etc., have been reported in the literature. In the present work, we investigated the H3 + + CO bimolecular reaction in the gas phase using direct dynamics methodology. The simulation conditions were chosen to mimic recently reported velocity map imaging experiments on the same reaction. The calculations were performed using the density functional PBE0/aug-cc-pVDZ level of electronic structure theory. Internal energy and scattering angle distributions of reaction products found from the simulations are in qualitative agreement with the experiment. However, the product branching ratios at low collision energies were in contrast with the experimental predictions. Interesting dynamical features were observed in the simulations, and detailed atomic level mechanisms are presented.

Dynamics of proton transfer from ArH+ to CO

“…This is in contrast to the HOCO + + CO reaction for which the HOC + product channel is endothermic, and the assumption of identical internal energy fractions of the total available energy for both isomers allowed the estimation of an upper limit of <2% for the HOC + fraction [27]. The present study suggests, that similar estimates for the H + 3 + CO reaction [14] may have resulted in too small limits for the HOC + fraction which is supported by recent direct dynamics simulations [43].…”

“…This would yield larger HOC + fractions for the reaction of H + 3 + CO than previously estimated. Such larger HOC + fractions are supported by recent chemical dynamics simulations [43], even though the simulated internal energy distributions do not quantitatively agree with the experiments.…”

Final-State-Resolved Dynamics of the H3+ + CO → H2 +HCO+/HOC+ Reaction: A Quasi-Classical Trajectory Study

“…Theoretically, Naz et al carried out direct dynamics calculations at the level of PBE0/aug-cc-pVDZ. 32 The obtained product internal energy and scattering angle distributions were in qualitative agreement with the experiment. Recently, our group developed an accurate potential energy surface (PES) for the H 3 + + CO reaction by fitting 46 462 ab initio points at the level of CCSD(T)-F12a/aug-cc-pVTZ.…”

Ring-Polymer Molecular Dynamics Calculations of Thermal Rate Coefficients and Branching Ratios for the Interstellar H3+ + CO → H2 + HCO+/HOC+ Reaction and Its Deuterated Analogue

“…Thus, theoretical prediction of various physical quantities is essential. Several theoretical studies have been performed. − For example, Le et al constructed a full-dimensional potential energy surface using an interpolation technique and performed quasi-classical trajectory (QCT) calculations . Zhu et al.…”