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

TL;DR

This study enhances classical trajectory calculations for OH+CH4/CD4 reactions by incorporating additional constraints, achieving remarkable agreement with experimental pair-correlated product distributions at high collision energy.

Contribution

The paper introduces improved classical trajectory simulation methods that better replicate experimental results for complex reaction dynamics in a quantum-inspired framework.

Findings

Enhanced agreement with experimental distributions

Classical calculations can be refined with additional constraints

High-dimensional reaction dynamics are accurately modeled

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 [B. Zhang, W. Shiu, J. J. Lin and K. Liu, J. Chem. Phys 122, 131102 (2005); B. Zhang, W. Shiu and K. Liu, J. Phys. Chem. 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.