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Rate constants for the reactions of F atoms with H 2 and D 2 over the temperature range 220‐960 K
Author(s) -
Bedjanian Yuri
Publication year - 2021
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.21462
Subject(s) - chemistry , reaction rate constant , deuterium , kinetic isotope effect , arrhenius equation , atmospheric temperature range , analytical chemistry (journal) , kinetic energy , quadrupole mass analyzer , chemical kinetics , hydrogen , kinetics , torr , mass spectrometry , atomic physics , thermodynamics , activation energy , physics , organic chemistry , quantum mechanics , chromatography
The kinetics of the reactions of F atoms with hydrogen and deuterium has been studied in a discharge flow reactor combined with an electron impact ionization quadrupole mass spectrometer at nearly 2 Torr total pressure of helium and in the temperature range 220‐960 K. The rate constant of the reaction F + H 2 → HF + H (1) was determined using both relative rate method (using reaction F + Br 2 as a reference) and absolute measurements, monitoring the kinetics of F atom consumption in excess of H 2 : k 1 = (1.24 ± 0.09) × 10 −10 exp(−(507 ± 23)/ T ) cm 3 molecule −1 s −1 . The rate constant of the reaction F + D 2 → DF + D (2) was measured under pseudo‐first‐order conditions in excess of D 2 over F atoms: k 2 = (8.47 ± 0.42) × 10 −11 exp(−(670 ± 16)/ T ) cm 3 molecule −1 s −1 (the uncertainties on both k 1 and k 2 represent precision at the 2 σ level, the estimated total uncertainty on the rate constants being 15% at all temperatures). The kinetic isotope effect measured independently, k 1 / k 2 = (1.58 ± 0.05) × exp((131 ± 2)/ T ), was found to be in excellent agreement (within 7% in the temperature range of the work, T = 220‐960 K) with the ratio of k 1 to k 2 calculated with the Arrhenius expressions for k 1 and k 2 determined in the study. The kinetic data from the present work are discussed in comparison with previous measurements and theoretical calculations.