Flash photolysis - shock tube technique using atomic resonance absorption for kinetic studies at high temperatures
A flash photolysis-shock tube technique is described for making kinetic measurements at high temperature. Coupled with sensitive atomic resonance absorption detection, this method allows bimolecular rate constants for atom-molecule reactions to be measured directly under conditions free from kinetic complications. Experiments were performed in the reflected shock regime, and the temperature and density were calculated using ideal shock wave theory in this initial work. Results for the reaction of atomic hydrogen with ammonia are presented to illustrate the potential of the technique. The values of the Arrhenius rate parameters found in these experiments, 900 K less than or equal to T less than or equal to 1850 K, were A = (1.14 +/- 0.12) x 10/sup -10/ cm/sup 3/ molecule/sup -1/ s/sup -1/ and E/sub ..cap alpha../ = 13,216 +/- 242 cal mol/sup -1/. This result gives rate constants that are about five times larger than those from previous studies. Although corrections for nonidealities in the reflected shock region are anticipated and under investigation, the expected changes will be relatively small and thus the large discrepancy noted here will remain. 21 references, 5 figures, 1 table.
- Research Organization:
- Brookhaven National Lab., Upton, NY
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 6012005
- Journal Information:
- Int. J. Chem. Kinet.; (United States), Vol. 17
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
47 OTHER INSTRUMENTATION
PHOTOLYSIS
RESONANCE ABSORPTION
CHEMICAL REACTION KINETICS
HIGH TEMPERATURE
SHOCK TUBES
ABSORPTION
CHEMICAL REACTIONS
DECOMPOSITION
KINETICS
PHOTOCHEMICAL REACTIONS
REACTION KINETICS
400500* - Photochemistry
440300 - Miscellaneous Instruments- (-1989)