Study of the kinetics of the reactions of NO3 with HO2 and OH

✍ Scribed by A. Mellouki; R. K. Talukdar; A. M. R. P. Bopegedera; Carleton J. Howard

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 856 KB
• Volume: 25
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550250104

✦ Synopsis

Abstract

The Absolute rate constants for the gas‐phase reactions of NO~3~ with HO~2~ and OH have been determined using the discharge flow laser magnetic resonance method (DF‐LMR). Since OH was found to be produced in the reaction of HO~2~ with NO~3~, C~2~F~3~Cl was used to scavenge it. The overall rate constant, k~1~, for the reaction, HO~2~ + NO~3~ → products, was measured to be k~1~=(3.0 ± 0.7)×10^−12^ cm^3^ molecule^−1^ s^−1^ at (297 ± 2) K and P=(1.4 – 1.9) torr. This result is in reasonable agreement with the previous studies. Direct detection of HO~2~ and OH radicals and the use of three sources of NO~3~ enabled us to confirm the existence of the channel producing OH:HO~2~+NO~3~→OH+NO~2~+O~2~ (1a); the other possible channel is HO~2~+NO~3~→HNO~3~+O~2~ (1b). From our measurements and the computer simulations, the branching ratio, k~1a~/(k~1a~ + k~1b~), was estimated to be (1.0). The rate coefficient for the reaction of OH with NO~3~ was determined to be (2.1 ± 1.0) × 10^−11^ cm^3^ molecule^−1^ s^−1^. © 1993 John Wiley & Sons, Inc.