OH- + CH3I --> CH3OH + I- SN2 Reaction
Following are animations of some representative trajectories showing different atomic-level mechanisms for the OH- + CH3I --> CH3OH + I- SN2 reaction. Initial conditions include relative translational energy between OH- and CH3I, Erel; CH3I vibrational and rotational temperatures Tv = 330 K and Tr = 130 K; and OH- vibrational and rotational temperatures Tvr = 100 K. The direct dynamics simulations were performed with the B97-1/ECP/d level of theory. The trajectories for the simulations were calculated with the VENUS chemical dynamics computer program interfaced with the NWChem electronic structure computer program. A 6th order symplectic algorithm with a 2.5 fs time step was used to integrate the trajectories. Reports of this research are given in Faraday Discussions Chemical Society 157, 41-57 (2012), Journal of Physical Chemistry A, 117, 7162-7178 (2015), and Journal of Physical Chemistry A, 117, 14019-14027 (2013).
OH- + CH3I --> HO---HCH2I --> CH3OH + I-, Nucleophilic substitution by indirect mechanism, involving barrier recrossing and formation of the HO---HCH2I hydrogen-bonded pre-reaction complex; Erel = 0.05 eV