Reactions of halogen oxides studied by flash photolysis II. The flash photolysis of chlorine monoxide and of the ClO free radical

The Royal Society - Tập 323 Số 1554 - Trang 401-415 - 1971
N. Basco, S.K. Dogra

Tóm tắt

A study of the flash photolysis of chlorine monoxide and of its photosensitized decomposition by chlorine and bromine has yielded rate constants for the reactions Cl + Cl2O → Cl2+ ClO,k1= 4.1 x 108l mol-1s-1, Br + Cl2O → BrCl + ClO,k9= 6.1 x 108l mol-1s-1, ClO + Cl2O → ClO2+ Cl2,k3= 2.6 x 105l mol-1s-1, ClO + Cl2O → Cl2+ O2+ Cl,k4= 6.5 x 105l mol-1s-1, 2ClO → Cl2+ O2,k2= 2.8 x 107l mol-1s-1. The quantum yield for the decomposition of chlorine monoxide was measured in each of the three systems and is quantitatively accounted for by the reactions given. The CIO free radical has been flash photolysed and the production of vibrationally excited oxygen in the reaction O + CIO → Cl + O*2(v"≼ 14),k11= 7.5 x 109l mol-1s-1demonstrated. The same reaction is responsible for the production of O*2in the flash photo­lysis of Cl2O with radiation below ~ 300 nm. The relaxation of O*2by chlorine atoms is exceptionally efficient, with a rate constant forv"= 12 in excess of 2 x 109l mol-1s-1. The corresponding rate constant for relaxation by Cl2O is < 108l mol-1s-1.

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