Accurate integral cross sections for the H + CO2 → OH + CO reaction

Gatti

2019

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The collision between hydrogen and ammonia is a benchmark system to study chemical elementary reactions with five atoms. In this work, we present a description of the system based on mixed Jacobi and Radau coordinates combined with the time-dependent wave packet method to study the H+NH 3 reaction. The Radau coordinates are used to describe the reactive moiety NH 2 . A salient feature of this approach is that the present coordinates have the great advantage that a very small number of basis set functions can be used to describe the NH 2 group. Potential-optimized discrete variable representation basis is applied for the vibrational coordinates of the reagent NH 3 . The reaction probabilities for several initial vibrational states are presented in this paper. The role of the different vibrational excitations on the reactivity is thoroughly described.

Section: Introductionmentioning

confidence: 99%

Full dimensional quantum mechanical calculations of the reaction probability of the H + NH3 collision based on a mixed Jacobi and Radau description

Gatti

2019

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Well converged quantum rate constants for the H2 + OH → H2O + H reaction via transition state wave packet

Chen

Liu

et al. 2018

Transition state wave packet calculations have been carried out to compute cumulative reaction probabilities for the H + OH reaction on the NN1 potential energy surface, as given in the work of Chen , from which well converged thermal rate constants for the reaction up to a temperature of 1000 K were obtained. It was found that both the centrifugal sudden approximation and the "--shifting" approximation slightly underestimated the thermal rate constants, while the ring-polymer molecular dynamics overestimated the rates in the low temperature region. After considering the correction of the barrier height by spin-orbit coupling effect and the more accurate level of theory, the calculated rate constants were in good consistency with experimental measurements in the entire temperature region for this benchmark reaction.

Full-dimensional quantum dynamics study of isotope effects for the H2 + NH2/ND2/NHD and H2/D2/HD + NH2 reactions

Gatti

et al. 2021

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A full-dimensional quantum dynamical study for the bimolecular reactions of hydrogen molecules with amino radicals for different isotopologues is reported. The nonreactive amino radical is described by two Radau vectors that are very close to the valence bond coordinates. Potential-optimized discrete variable representation basis is used for the vibrational coordinates of the amino radical. Starting from the reaction H2 + NH2, we study the isotope effects for the two reagents separately, i.e., H2 + NH2/ND2/NHD and H2/D2/HD + NH2. The effects of different vibrational mode excitations of the reagents on the reactivities are studied. Physical explanations about the isotope effects are also provided thoroughly including the influence of vibrational energy differences between the different isotopologues and the impact of the tunneling effect.