Roaming radicals in the thermal decomposition of dimethyl ether: Experiment and theory

Please cite this article in press as: R. Sivaramak The thermal dissociation of dimethyl ether has been studied with a combination of reflected shock tube experiments and ab initio dynamics simulations coupled with transition state theory based master equation calculations. The experiments use the extraordinary sensitivity provided by H-atom ARAS detection with an unreversed light source to measure both the total decomposition rate and the branching to radical products versus molecular products, with the molecular products arising predominantly through roaming according to the theoretical analysis. The experimental observations also provide a measure of the rate coefficient for H + CH3OCH3. An evaluation of the available experimental results for H + CH3OCH3 can be expressed by a three parameter Arrhenius expression as, k 1⁄4 6:54 10 T expð 896=TÞ cm molecule 1 s ð273 1465 KÞ