title: CH stretching excitation in the early barrier F + CHD3 reaction inhibits CH bond cleavage.
abstract: Most studies of the impact of vibrational excitation on molecular reactivity have focused on reactions with a late barrier (that is, a transition state resembling the products). For an early barrier reaction, conventional wisdom predicts that a reactant's vibration should not couple efficiently to the reaction coordinate and thus should have little impact on the outcome. We report here an in-depth experimental study of the reactivity effects exerted by reactant C-H stretching excitation in a prototypical early-barrier reaction, F + CHD3. Rather counterintuitively, we find that the vibration hinders the overall reaction rate, inhibits scission of the excited bond itself (favoring the DF + CHD2 product channel), and influences the coproduct vibrational distribution despite being conserved in the CHD2 product. The results highlight substantial gaps in our predictive framework for state-selective polyatomic reactivity.
authors.affiliation: Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Post Office Box 23-166, Taipei, 10617 Taiwan.
authors.forename: Weiqing
authors.initials: W
authors.lastname: Zhang
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawamata
authors.forename: Kopin
authors.initials: K
authors.lastname: Liu