A Quantitative study of alkyl radical reactions by kinetic spectroscopy. Part I. Mutual combination of methyl radicals and combination of methyl radicals with nitric oxide

Combination reactions of the methyl radical have been studied by following the decay of the absorbance of the methyl radical during the course of the reaction by means of kinetic spectroscopy. The limiting values of the second‐order rate constants at high pressure were determined for two reactions at room temperature:\documentclass{article}\pagestyle{empty}\begin{document}$ \begin{array}{*{20}c} {{\rm CH}_{\rm 3} + {\rm CH}_{\rm 3} ( + {\rm M}) \to {\rm CH}_{\rm 3} {\rm CH}_{\rm 3} ( + {\rm M}):k_1 = (2.6 \pm 0.3) \times 10^{10} 1{\rm mole}^{ - {\rm 1}} \sec ^{ - 1} } \\ {{\rm CH}_{\rm 3} + {\rm NO }( + {\rm M}) \to {\rm CH}_{\rm 3} {\rm NO }( + {\rm M}):k_2 = (2.4 \pm 0.2) \times 10^9 1{\rm mole}^{ - {\rm 1}} \sec ^{ - 1} } \\ \end{array} $\end{document}The extinction coefficient of the methyl radical was found to have a maximum value of (1.02 ± 0.06) X 10 4 1 mole −1 cm −1 at 216.4 nm. Integration of the extinction coefficient over the absorption band of the methyl radical gave an oscillator strength of 1.0 X 10 −2 .