Correlation between the velocity scattering angle and product relative translational energy for SN2 reactions. Comparison of experiments and direct dynamics simulations

In previous research, direct dynamics simulations have been used to provide atomistic information for the Cl-+ CH3I, F-+ CH3I, and OH-+CH3I S(N)2 and proton transfer (PT) reactions. An important component of these simulations is comparison with molecular beam, ion imaging experiments. From the simulations, comparisons may be made with the product translational energy distributions determined from the experiments and the simulations give quite good agreement with these distributions. Though the experiments provide the in-plane angular distribution for a reaction's product translational energy distribution, the number of direct dynamics trajectories for a simulation is not sufficient to compare with this angular distribution. In the work presented here, the average percentage product translational energy partitioning for forward scattered events with scattering angle theta= 0-90 degrees and for backward scattered events with theta=90-180 degrees are compared for the experiments and simulations. Overall good agreement is found, with a maximum difference as high as 5-10%. Additional atomistic details, regarding the dynamics of these reactions, are provided by scatter plots of their product relative translational energy versus the scattering angle theta. (C) 2019 Elsevier B.V. All rights reserved.