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Study of the kinetics of the reactions of NO 3 with HO 2 and OH
Author(s) -
Mellouki A.,
Talukdar R. K.,
Bopegedera A. M. R. P.,
Howard Carleton J.
Publication year - 1993
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550250104
Subject(s) - chemistry , reaction rate constant , analytical chemistry (journal) , radical , branching fraction , torr , kinetics , molecule , gas phase , branching (polymer chemistry) , chemical reaction kinetics , chemical kinetics , atomic physics , organic chemistry , thermodynamics , physics , quantum mechanics
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 −0.3 +0.0 ). 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.