Abstract
Rainbow structure in the scattering angular distribution plays an important role in deepening our understanding about atoms/molecules collisions. It is a quantum interference phenomenon and has been extensively studied for decades in the elastic and rotationally inelastic processes. In a recent study of the chemical reaction of F + CH3D, an intriguing bulge feature was discovered in the pair-correlated angular distribution of the CH2D(00) + HF(v = 3) channel, which was interpreted as the rainbow effect in chemical reaction. Further conjectures were put forward, suggesting that reactive rainbow could be a general phenomenon provided that three conditions were met. One of the conditions is that the reactive event behaves elastic-like. To test the hypotheses, this work turns to the alternative isotopic product channel, CH3 + DF, and examines the dynamical attributes over a wide range of collision energy (Ec) from about 2.1–19.5 kJ mol−1. We found that similar bulge features indeed appear in another isoergic channel of CH3(00) + DF(v = 4). Moreover, an inverse-linear Ec-dependency of the bulge angle was clearly established, reminiscent of the key relationship in characterising the l-type rainbow of elastic collisions.
A l-type rainbow is manifested as the angular bulge in the isoergic product channels of a chemical reaction.
GRAPHICAL ABSTRACT
Acknowledgements
This work was supported by the Academia Sinica and the Minister of Science and Technology of Taiwan (MOST-105-2113-M-001-019-My3).
Disclosure statement
No potential conflict of interest was reported by the author(s).
ORCID
Sohidul Mondal http://orcid.org/0000-0002-0877-2895
Kopin Liu http://orcid.org/0000-0001-7499-2397