SHOCK-TUBE MEASUREMENTS OF RATE COEFFICIENTS OF ELEMENTARY GAS REACTIONS

The primary objective of this paper is to review the current status of rate coefficient determinations of elementary gas reactions using modern shock tube measurement techniques. The major inaccuracies in these determinations arise from uncertainties in reaction conditions due to gas dynamic effects, uncertainties introduced by interfering rate processes such as vibrational relaxation, competing reactions, or reactions involving impurities, and uncertainties introduced by the diagnostics. Some new diagnostics and experimental methods which can improve accuracy of shock tube rate coefficient measurements are discussed. Included among these are tunable laser absorption spectroscopy for species concentration and temperature measurements, digital data recording, new techniques for controlled generation of radical species, and computer optimization of experimental conditions. Currently attainable levels of accuracy of shock tube rate coefficient determinations of elementary gas reactions are illustrated for several classes of reactions including unimolecular decomposition reactions, bimolecular atom-molecule exchange reactions, and termolecular recombination reactions. © 1979 American Chemical Society.