Reaction kinetics at very low temperatures: laboratory studies and interstellar chemistry.

Studies of gas-phase processes at temperatures down to 10 K have recently blossomed, largely through application of the CRESU (cinétique de réaction en ecoulement supersonique uniforme) technique. The results are of considerable relevance to the synthesis of molecules in dense interstellar clouds, demonstrating that the models developed to explain the observed molecular abundances must be expanded to include reactions between electrically neutral species. In addition, the experimental results have stimulated theoretical efforts to describe the factors that control the rates of such low-temperature reactions. In this Account, the CRESU method is described and the relevance of the results discussed.