G. Laverdet

Kinetics of the reactions of atomic bromine with HO2 and HCO at 298 K

The rate constants for the reactions Br+HCO→HBr+CO (2) and Br+HO2→HBr+O2 (4) have been measured at 298 K by the discharge flow technique coupled to laser induced fluorescence and mass spectrometry for detection of reactive species. HO2 radicals were generated by reacting atomic bromine with formaldehyde using an excess of O2, and were monitored after conversion into OH and NO2 with added excess NO. k2 and k4 were found to be (2.8±1.2)×10−10 and (7.6±0.9)×10−13cm3 molecule −1u2009s−1, respectively. The experimental kinetic curves were also compared to the predicted profiles obtained from computer simulation of the chemical system used. Although k4 is found to be 3–4 times higher than an earlier direct measurement, this result confirms that HBr is not an efficient reservoir for stratospheric bromine.

Kinetic study of the reaction of OH radicals with nitrosyl chloride as a possible source of ClOH

Abstract The reaction of OH with NOCl has been studied using the discharge flow reaction-EPR technique. The absolute rate constant is k1 = (4.3±0.4)× 10−13 cm3 molecule−1 s−1 at 298 K. A mass spectrometric investigation of the products shows that this reaction occurs via two primary steps, OH + NOCl → NO + ClOH(1a) and OH + NOCl → HONO + Cl (1b) with k1a =k1b.

The BrO + C1O Reaction and the Polar Stratospheric Ozone

The rate constant of the title reaction has been measured at 298 K using the discharge flow - mass spectrometry method: k1 = (1.13 ± 0.15) X 10-11 cm3 molecule-1s-1. The measurement of the products has led to the determination of the branching ratios: (0.43 ± 0.10) for the 0C10 channel and (0.12 ± 0.05) for the BrC1 one at 298 K.