The thermal unimolecular isomerization reactions of cycloheptatriene, and of methyl- , ethyl- , and isopropyl-cycloheptatriene, have been studied over the temperature range 900–1400 K in shock waves. Even for these large molecules, falloff behavior has to be taken into account mainly due to weak collision effects. The limiting high pressure rate constants k∞ and the specific rate constants k (E) are derived for use in later photoactivation experiments.

Rate constants for the spin-forbidden dissociation process SO3+Ar→SO2+O+Ar have been measured in shock waves between 1700 and 2500 K. The results are compared with data on the low temperature (200–400 K) recombination reaction. The analysis in terms of unimolecular reaction rate theory allows for a determination of the threshold energy of the reaction.

Absorptionsspektren, sichtbar und ultrauiolett / Freie Radikale / Reaktionskinetik / StojwellenThe ultraviolet absorption spectra of substituted cycloheptatrienes, toluene, p-xylene, and of benzyl and methyl-benzyl radicals have been measured in shock waves at temperatures between 700 and 1650 K. The temperature dependence of the spectra is compared with an analysis based on the deltafunction method in various approximations. The measurements allow for the prediction of the shape of microcanonically hot spectra of laser excited molecules.

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