State selective reactions prepared through the excitation of orbital states in van der Waals complexes of Ca–HX*

Soep, B.; Abbès, S.; Keller, A.; Visticot, J. P.
January 1992
Journal of Chemical Physics;1/1/1992, Vol. 96 Issue 1, p440
Academic Journal
We have observed the chemiluminescent reaction Ca*+HX→CaX*+H, where the reactants are prepared in a van der Waals complex formed in a supersonic expansion. This preparation, combined with tunable laser excitation, allows access to well-defined electronic states of the reaction complex corresponding to different orientations of the calcium excited orbital. In the case of the Ca–HBr complex, a remarkable effect of this preparation is observed on the branching ratio to the final excited states A 2Π and B 2Σ of CaBr: Depending upon the selected state of the complex, the A/B ratio varies by a factor of 2. This is interpreted by the conservation of the orbital orientation during the reaction involving the departure of the hydrogen.


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