High-level analytical potential-energy-surface-based dynamics of the OH - + CH 3 CH 2 Cl S N 2 and E2 reactions in full (24) dimensions.

We develop a coupled-cluster full-dimensional global potential energy surface (PES) for the OH - + CH 3 CH 2 Cl reactive system, using the Robosurfer program package, which automatically samples configurations along PES-based trajectories as well as performs ab initio computations with Molpro and fitting with the monomial symmetrization approach. The analytical PES accurately describes both the bimolecular nucleophilic substitution (S N 2) and elimination (E2) channels leading to the Cl - + CH 3 CH 2 OH and Cl - + H 2 O + C 2 H 4 products, respectively, and allows efficient quasi-classical trajectory (QCT) simulations. QCT computations on the new PES provide accurate statistically-converged integral and differential cross sections for the OH - + CH 3 CH 2 Cl reaction, revealing the competing dynamics and mechanisms of the S N 2 and E2 ( anti , syn , β-α transfer) channels as well as various additional pathways leading to induced inversion of the CH 3 CH 2 Cl reactant, H-exchange between the reactants, H 2 O⋯Cl - complex formation, and H 2 O + CH 3 CHCl - products via proton abstraction.