Pair-correlated speed distributions for the OH+CH4/CD4 reactions: Further remarks on their classical trajectory calculations in a quantum spirit

Abstract

Ten years ago, Liu and co-workers measured pair-correlated product speed and angular distributions for the OH+CH4/CD4 reactions at the collision energy of ∼ 10 kcal/mol [A 2005, 109, 8989]. Recently, two of us could semi-quantitatively reproduce these measurements by performing full-dimensional classical trajectory calculations in a quantum spirit on an ab-initio potential energy surface of their own [J. Espinosa-Garcia and J. C. Corchado, Theor Chem Acc, 2015, 134, 6 ; J. Phys. Chem. B, Article ASAP, DOI: 10.1021/acs.jpcb.5b04290]. The goal of the present work is to show that these calculations can be significantly improved by adding a few more constraints to better comply with the experimental conditions. Overall, the level of agreement between theory and experiment is remarkable considering the large dimensionality of the processes under scrutiny.

Full-Dimensional Theory of Pair-Correlated HNCO Photofragmentation

“…We wish to emphasize that the quality of the accord for both wave lenghts would be lost without respecting Bohr quantization, as recently illustrated in Ref. [35]. The dashed curves in the left panels are the CO vibrational state contributions to the total KED.…”

“…As in the previous case, more energy is channeled into the rotational motion of CO than into the one of 1 NH. We wish to emphasize that the quality of the accord for both wavelengths would be lost without respecting Bohr quantization, as recently illustrated in ref .…”

Capturing quantum effects with quasi-classical trajectories in the D + H+3 → H2D+ + H reaction

“…QCT with Gaussian binning has been remarkably successful in matching measurements and quantum scattering results for reaction rates and product state distributions including the reactions: O( 3 P) + HCl, OH + CO, and O( 3 P) + H 2 O. [20][21][22][23][24] ''QCT in a quantum spirit'' which can straightforwardly prepare reactant states and analyze product state distributions, if sufficiently accurate, would be highly desirable. Can a relatively inexpensive classical trajectory method, suitably weighted, work for D + H + 3 ?…”

Global potential energy surface and product pair-correlated distributions for the F(2P) + SiH4 reaction – comparison with experiments

“…In order to avoid or at least correct this overestimation, intimately related with the classical nature of the QCT calculations, and so that theory/experiment comparisons are performed on the same footing, we introduce here some QCT constraints so that classical trajectories can be analysed in a quantum spirit. 2,56,57 Obviously, these constraints are artificial, not based on sound theoretical arguments, and so in the absence of QM calculations they represent a first approximation to the problem. Experimentally 10 little rotational excitation was observed for the SiH 3 and HF products, about 5–7% of the available energy, which represents ∼2–3 kcal mol −1 as rotational energy.…”