Dynamics of the O(3P) + CH4 hydrogen abstraction reaction at hyperthermal collision energies

Abstract

Motivated by recent experiments on the title reaction at the high collision energy of 64 kcal mol⁻¹ reported by Minton et al., a detailed dynamics study was carried out using quasi-classical trajectory (QCT) calculations based on an analytical potential energy surface recently developed by our group, PES-2014. Our results reproduce the experimental evidence: most of the available energy appears as translational energy (80 ± 10%) and scattering distribution is forward, suggesting a stripping mechanism associated with high impact parameters. Of special interest is the triple (angle-velocity) differential cross section (a combination of translational and scattering distributions), which shows the same structure associated with the products. Agreement with experiment lends confidence to the new PES-2014 surface; this is encouraging, furthermore, because its fitting was made with thermal behaviour in mind, and higher energy areas were neither sampled nor weighted sufficiently.