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

Abstract

The ion–molecule reaction H3 + + CO → H2 + HCO+/HOC+, which initiates the formation of crucial organic molecules, plays a key role in interstellar and circumstellar environments. In this work, the quasi-classical trajectory method is employed to study the reaction dynamics on a recently developed full-dimensional global potential energy surface (PES). The calculated product internal energy distributions and relative internal excited fractions agree reasonably well with the experimental measurements. For the two reaction channels, most of the available energy flows into the vibrational modes of HCO+ or HOC+ at low collision energies, followed by the translational mode and the rotational modes of HCO+ or HOC+. As the collision energy increases, the proportion of the product translational energy increases while the proportion of the product vibrational energy decreases. Furthermore, the CH and CO stretching modes and their combination bands are effectively excited for the product HCO+ while the bending mode is remarkably excited for the product HOC+.

Kinetic and dynamic studies of the NH2+ + H2 reaction on a high-level ab initio potential energy surface

“…It should be noted that applying ''ZPE constraints'' sometimes can lead to unphysical results. 23,63 We did not present the dynamic and kinetic results with the ZPE constraints in this work.…”

Proton leap: shuttling of protons onto benzonitrile

“…Such reactions in the interstellar medium have been extensively studied both experimentally and theoretically. 2–13 It is believed that some of them play an important role in the synthesis of prebiotic oligopeptides. 14 Based on theoretical calculations, Redondo et al 10 suggested that reaction between CH 5 + and NH 2 CHO might result in formation of acetamide in the interstellar medium.…”

“…Spesyvyi, Smith and Španěl 12 studied reactions of H 3 O + , NO + , and O 2 + with saturated aliphatic ketones and provided both experimental and theoretical estimation of the corresponding rate constants. Song and coworkers 13 used a quasi-classical trajectory method to study products (stable HCO + and metastable HOC + ) resulting from collision of H 3 + with CO, their internal energy distributions, and relative internal excited fractions. They demonstrated that the excess vibrational energy is located in the CH and CO stretching modes of the charged particles.…”

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.…”

“…constructed a potential energy surface by fitting over 46,000 points calculated at the highly accurate CCSD­(T)-F12a/aug-cc-pVTZ level using the machine-learning neural network technique . They also calculated reactive cross-sections, thermal rate coefficients, and product branching ratios using QCT calculations, where the quantized zero-point vibrational energy was considered in a classical manner. , They found that the magnitude of reactive cross sections depends on how the zero-point energy is incorporated into the classical trajectory calculations. This suggests that the zero-point energy leakage affects the reaction dynamics substantially and that the importance of the nuclear quantum effects in the H 3 + + CO reaction should be carefully considered.…”