Pair-Correlated Imaging of Cl + CH3D(v4, v1-I, v1-II=1, |jK⟩) → CH2D(vi) + HCl(v)

The title reactions were studied at a collisional energy of 10.0 kcal mol(-1) in a crossed-beam, product-imaging experiment. In terms of integral cross sections, all three CH3-stretching excited CH3D(v(CH3) = 1) reagents promote the reactivity in forming the predominant product pair of (v(CH2D), v(HCl))(s) = (0(0), 0/1)(s) with a prominent mode-propensity of v(4) > v(1)-I > v(1)-II, where v(4) denotes the degenerate mode of CH3 asymmetric stretch and v(1)-I and v(1)-II are a pair of Fermi-coupled, symmetric-stretch states. The vibrationally excited CH2D product pairs of (6(1), 0) s, (1(1), 0)(s), and (31, 0) s appear to be minor channels and display a reverse propensity of v(4) < v(1)-I approximate to v(1)-II for (61, 0)(s), while v(4) > v(1)-I for (11, 0)(s). Based on the observed angular distributions, we conjecture that, irrespective of the initial mode of excitation, the (0(0), 0)(s) product pair proceeds by a direct abstraction of the peripheral type, whereas the (0(0),1)(s) pair is mediated via a resonance pathway. Intriguingly, the angular distributions of the excited product pairs-(6(1), 0)(s), (1(1), 0)(s), and (3(1), 0)(s)-are remarkably similar and comprise the traits of both the peripheral mechanism and resonance pathway. Possible interpretation and implication are suggested. In addition, due to the spectral overlap of the REMPI bands and heavily congested image features, a robust data analysis method is developed, which enables us to extract the dynamics attributes of a weak feature buried in the proximate, more intense ones with high fidelity.