Measuring the spectra, products of reaction, and (in)elastic collisions of astrochemical species using rotational spectroscopy
Résumé
The interstellar medium is a unique environment where low temperatures can produce interesting physical and chemical conditions. Cold reactions can produce species that not commonly observable on Earth while non-reactive collisions can leave molecules out of thermodynamic equilibrium with their environment. These physical and chemical processes can be modelled with sufficient laboratory or theoretical data, where new techniques help to increase relevance or accuracy of this data. Rotational spectroscopy has been an incredible tool to compare spectra recorded in observations and the laboratory to identify molecules, but applications towards measuring reactive and non-reactive collisional data is growing. The rotational spectra of molecules of astrochemical interest were recorded under cold and warm conditions, supplying spectra but also the collisional properties of these species. Spectra of organohalogen molecules were recorded up to 500 GHz to enable their detection in the interstellar medium. The difference in collisional interaction between HCN and HNC with He was measured down to low temperatures, validating theory predictions of this difference and its importance in collisional (de)excitation mechanisms. Finally, the products from reactions of CN radicals were measured down to low temperatures using uniform flow experiments. These experimental results and their implications towards astrochemistry will be discussed.