Determination of Kinetic Parameters in Laminar Flow Reactors. II. Experimental Aspects

Abstract

In the present contribution laser spectroscopic studies are described in which the chemical kinetics of benchmark elementary reaction steps in different laminar flow reactors were experimentally investigated along with detailed numerical modeling calculations (see the article Carraro/Heuveline/Rannacher [5] in this vol-ume). Coherent anti-Stokes Raman spectroscopy (CARS) was utilized to study the collisional relaxation and vibrational energy transfer of vibrationally excited molec-ular hydrogen H2(v = 1) in a low-temperature discharge flow reactor (T = 110 — 300 K). In theses studies wall deactivation probabilities and thermal rate constants for the vibrational energy transfer gas-phase reaction H2(v = 1) + D2(v = 0) → D2(v = 1) + H2(v = 0) could be derived from a direct comparison of measured con-centration profiles with results from a detailed numerical modeling. Further experi-ments were performed, in which CARS for molecular hydrogen detection along with OH laser-induced fluorescence (LIF) spectroscopy was utilized to determine the rate constant for the gas-phase reaction OH + H2(v = 1) → H + H2O. Finally a high-temperature flow reactor setup will be described, which allows for kinetics studies of elementary reactions using the pulsed laser photolysis (LP)/laser induced fluores-cence (LIF) pump-and-probe technique. The latter technique was employed in the present work to investigate the temperature dependence of the reaction of electron-ically excited oxygen atoms with molecular hydrogen, O(1D) + H2 → H + OH.