Low-temperature Chemistry in Uniform Supersonic Flows

The behaviour of gas-phase chemical reactions at low temperatures (below 200 K) is of fundamental interest, but also of relevance to a variety of natural environments, either Earth-bound, such as the upper troposphere and the stratosphere, or extraterrestrial, such as the atmospheres of other planets and their satellites, comets, and interstellar clouds. In this work we review the role that chemical reactions play in these environments, and describe the most important processes under these conditions. We briefly describe the main techniques available for the study of gas-phase chemical kinetics at low temperatures, down to around 10 K, before concentrating in detail on the CRESU (cinétique de réaction en ecoulement supersonique uniforme or reaction kinetics in uniform supersonic flow) technique and its combination with a wide range of modern chemical kinetics methods. We then illustrate this technique with a range of case studies which show its application to problems of interest not only in their own right but also for atmospheric, interstellar, and planetary atmospheric chemistry.