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Multidimensional steric effect for the XeBr* (B, C) formation in the oriented Xe*((3)P2, M(J) = 2) + oriented CF3Br
1Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan. ohyama@chem.sci.osaka-u.ac.jp
The Journal of Chemical Physics
|June 25, 2010
Summary
Steric effects in XeBr(*) formation were studied by controlling molecular and atomic orientations during collisions. Different orientations favor different XeBr(*) product channels, suggesting a back-electron transfer mechanism for dark channels.
Area of Science:
- Chemical Physics
- Molecular Dynamics
- Reaction Mechanisms
Background:
- Investigating steric effects in chemical reactions provides insight into reaction dynamics and mechanisms.
- The Xe + CF3Br reaction system is a model for studying halogen atom and molecule interactions.
- Understanding orientation-dependent reactivity is crucial for controlling chemical transformations.
Purpose of the Study:
- To elucidate the steric effects in the formation of XeBr(*) (B, C) from oriented Xe(*) and oriented CF3Br.
- To determine the influence of atomic orbital alignment on the molecular steric opacity function.
- To differentiate the reaction pathways leading to XeBr(*) (B) and XeBr(*) (C) states.
Main Methods:
- Experimental observation of steric effects in the Xe(*) + CF3Br reaction.
- Determination of molecular steric opacity functions as a function of atomic orbital alignment (L(Z)') in the collision frame.
- Analysis of product channel selectivity based on reactant orientations.
Main Results:
- Significant differences in L(Z)' selectivity were observed between XeBr(*) (B) and XeBr(*) (C) channels.
- Specific alignments (L(Z)'=0 or |L(Z)'|=1) favor different product channels and orientations (molecular axis vs. sideway).
- A similarity in steric opacity function shapes was noted between specific alignments of the B and C channels.
Conclusions:
- The study reveals a strong dependence of XeBr(*) formation on the mutual orientation of reactants.
- An indirect mechanism involving back-electron transfer from the CF3 segment is proposed for dark channels.
- This mechanism explains the significant molecular alignment dependence observed in the reaction.
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