Chemical dynamics simulations were performed to study the atomistic details of gas phase reaction: F atom + CH3CN → HF + CH2CN. Potential energy profile obtained by quantum chemical calculations shows a release of 40-45 kcal/mol from reactants to products formation, making it an exothermic reaction. The pure gas phase transition state (TS) for this reaction has a structure represented by F--H--CH2CN, where the F—H bond begins to form as the H—C bond breaks. Micro solvated TS structure can be represented by CNH2C--H--F--HCH2CN where one H—C bond is elongated and is more likely to break as H—F bond is formed. The post transition state reaction dynamics were initiated at the TS with a Boltzmann distribution of energy as assumed by transition state theory (TST). The trajectories for the simulations were calculated with the VENUS chemical dynamics computer program interfaced with the NWChem electronic structure computer program. The trajectories show that H—F bond formation and C—H bond dissociation occur in a concerted step. Product formation is quiet rapid. The average time for first signature of H—F formation is only 3.8 fs. The population of vibrational states of HF molecules formed has been compared with experimental measurement done in gas phase and liquid phase. Of principal interest from these simulations is the manner in which the available energy is partitioned to the products translational, rotational and vibrational degrees of freedom.

Post-transition state dynamics and micro solvation effects of F atom + CH3CN → HF + CH2CN exothermic reaction

252nd National Meeting (2016)

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