High-level analytical potential-energy-surface-based dynamics of the OH + CHCHCl S2 and E2 reactions in full (24) dimensions.

We develop a coupled-cluster full-dimensional global potential energy surface (PES) for the OH + CHCHCl reactive system, using the Robosurfer program package, which automatically samples configurations along PES-based trajectories as well as performs computations with Molpro and fitting with the monomial symmetrization approach. The analytical PES accurately describes both the bimolecular nucleophilic substitution (S2) and elimination (E2) channels leading to the Cl + CHCHOH and Cl + HO + CH 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 + CHCHCl reaction, revealing the competing dynamics and mechanisms of the S2 and E2 (, , β-α transfer) channels as well as various additional pathways leading to induced inversion of the CHCHCl reactant, H-exchange between the reactants, HO⋯Cl complex formation, and HO + CHCHCl products proton abstraction.