98 research outputs found
Correlated Dynamics of the O(P-3) + CHD3(v=0) Reaction : A Joint Crossed-Beam and Quasiclassical Trajectory Study
Crossed beam experiments and quasiclassical trajectory computations on an ab initio potential energy surface are performed for the O(P-3) + CHD3(v=0) --> OH(V'=0) + CD3(v(2)=0,2) and OD(v'=0,1) + CHD2(v=0) reactions. Both experiment and theory show that the excitation functions display a concave-up behavior and the angular distributions are backward scattered, indicating a direct rebound mechanism and a tight-bend transition state. The reaction produces mainly ground-state products showing the dominance of a vibrationally adiabatic reaction pathway. The Standard histogram binning cannot reproduce the observed vibrational adiabaticity, Whereas Gausgian binning give good agreement with experitnent
Observation of a Reactive Rainbow in F + CH<sub>3</sub>D → CH<sub>2</sub>D(<i>v</i> = 0) + HF(<i>v</i> = 3)?
Rainbow structures in the scattering
angular distribution play
an important role in deepening our understanding about the elastic
and rotationally inelastic collisions of atoms/molecules. Reported
here is the discovery of a rainbow in a chemical reaction. At <i>E</i><sub>c</sub> = 4.3 kcal mol<sup>–1</sup> one of
the correlated product pairs in the F + CH<sub>3</sub>D reaction,
(<i>v</i><sub>HF</sub>, <i>v</i><sub>CH2D</sub>) = (3, 0<sub>0</sub>), displays a distinct bulge in angular distribution.
We showed that the bulge originates predominantly from the low-<i>j</i> states of the HF(<i>v</i> = 3) products. Heuristic
considerations led us to propose that such a bulge could be regarded
as a signature for rainbow scattering. The underlying mechanism for
its occurrence in this nearly thermoneutral product pair is ascribed
to a delicate interplay of the attractive and repulsive parts of interactions
in the vicinity of the transition state. In a sense, the situation
bears striking similarity to the more familiar elastic rainbow, thus
coined “reactive rainbow”
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