Carbon atom addition reactions leading to complexity in interstellar ices (How to marry laboratory and computational astrochemistry)
Abstract
The darkness readily observed between the stars on a clear night sky is far from empty. In fact, a large variety of molecules has been detected in the gas phase. They make up about 99% of the total mass in the Interstellar Medium (ISM). The final 1% of mass in the ISM is brought about by dust grains that once were expelled by dying stars. I focus primarily on the cold, dense molecular medium where surface reactions lead to the build-up of 'dirty' ices, forming a molecular mantle covering the micron-sized dust grains. Species accrete, diffuse, and react on the surface after which they can evaporate back into the gas phase. The interplay between these processes determines which molecules are formed, where, and whether or not they are astronomically observable, either in the solid or gas phase. Confirmation or exclusion of reaction pathways is possible experimentally, however, in order to quantitatively disentangle the relative importance on realistic amorphous ices I make use of computational chemistry. This way I aim to provide coarse-grained astrochemical models with crucial input parameters, such as branching ratios, binding energies, rate constants, and energy dissipation efficiencies. In this talk I will touch upon the reactions of (3P)C atoms with water and molecular hydrogen and I will show that an intricate interplay of reactions can lead to the formation of formaldehyde and methane, respectively. I will discuss this both from an experimental and computational point-of-view and link the various intermediates to other recent studies.
- Publication:
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44th COSPAR Scientific Assembly. Held 16-24 July
- Pub Date:
- July 2022
- Bibcode:
- 2022cosp...44.2746L