Vibrational mode-specific dynamics of the F + CHCHCl multi-channel reaction.

We investigate the mode-specific dynamics of the ground-state, C-Cl stretching (), CH wagging (), sym-CH stretching (), and sym-CH stretching () excited F + CHCHCl( = 0, 1) [ = 10, 7, 1, 3] → Cl + CHCHF (S2), HF + CHCHCl, FH⋯Cl + CH, and Cl + HF + CH (E2) reactions using a full-dimensional high-level analytical global potential energy surface and the quasi-classical trajectory method. Excitation of the C-Cl stretching, CH stretching, and CH/CH stretching modes enhances the S2, proton abstraction, and FH⋯Cl and E2 channels, respectively. -E2 dominates over -E2 (kinetic -E2 preference) and the thermodynamically-favored S2 (wider reactive -E2 attack angle range). The direct (a) S2, (b) proton abstraction, (c) FH⋯Cl + CH, (d) -E2, and (e) -E2 channels proceed with (a) back-side/backward, (b) isotropic/forward, (c) side-on/forward, (d) front-side/forward, and (e) back-side/forward attack/scattering, respectively. The HF products are vibrationally cold, especially for proton abstraction, and their rotational excitation increases for proton abstraction, -E2, and -E2, in order. Product internal-energy and mode-specific vibrational distributions show that CHCHF is internally hot with significant C-F stretching and CH wagging excitations, whereas CH is colder. One-dimensional Gaussian binning technique is proved to solve the normal mode analysis failure caused by methyl internal rotation.