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Photochemistry of dibromine peroxide, BrOOBr
Wiem Chebbi1,2, Najoua Derbel1,3, Thibaud Cours2
1LSAMA, Laboratoire de Spectroscopie Atomique Moléculaire et Applications, Department of Physics, University Tunis - El Manar, 1060 Tunis, Tunisia.
None:
The photochemistry of dibromine peroxide was investigated by means of mixed quantum-classical trajectory calculations on seven coupled potential energy surfaces. Photoexcited BrOOBr disintegrates rapidly, at a rate comparable with thermal decomposition. The rate constant is J = 9.7 × 10-2 s-1. The mechanism was investigated, and the final photolysis products are shown to be mainly 2Br + O2, though there is a minor channel leading to 2BrO. Their formation involves an unusual intermolecular vibronic energy redistribution process. A hitherto unknown isomer of BrOOBr, the van der Waals complex O2(a1Δg)·Br2(X1Σ+g), was found, which is more stable than the peroxide by 1.2 mEh.
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