Towards molecular complexity in interstellar ices

Thanja Lamberts, Assistant Professor at Leiden Institute of Chemistry and Leiden Observatory gives the lecture Towards molecular complexity in interstellar ices

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. The final 1% of the mass is contained in micron-sized dust grains that once were expelled by dying stars.  
In cold, dense interstellar regions, atoms and molecules adsorb, diffuse, and react on the surfaces of these dust grains, after which they can evaporate back into the gas phase. This leads to the build-up of molecular icy mantles of up to 100 monolayers thick. The interplay between the different surface processes determines which molecules are formed, where, and whether or not they are astronomically observable, either in the solid or gas phase. In order to quantitatively disentangle the relative importance on realistic amorphous ices, one can make use of computational chemistry. This way I and my group 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 focus on surface processes of molecules containing elements crucial to life, CHONS, and known to be present in cold interstellar regions to illustrate how binding, reactivity and dissipation go hand in hand. I aim to show the multi-faceted aspects of astrochemistry, linking our work to observational astronomy, and recent results obtained with the James Webb Space Telescope in particular.