Formation of c-C6H5CN ice using the SPACE TIGER experimental setup

Benzonitrile (c-C6H5CN) has been recently detected in cold and dense regions of the interstellar medium (ISM), where it has been used as a signpost of a rich aromatic organic chemistry that might lead to the production of polycyclic aromatic hydrocarbons (PAHs).

One possible origin of this benzonitrile is interstellar ice chemistry involving benzene (c-C6H6) and nitrile molecules (organic molecules containing the −C≡N group). We have addressed the plausibility of this c-C6H5CN formation pathway through laboratory experiments using the SPACE TIGER experimental setup.

We have irradiated c-C6H6:CH3CN ice mixtures with 2 keV electrons (Experiments 3-5) and Ly-alpha photons (Experiment 6), and compared the results with those obtained after 2 keV electron irradiation of c-C6H6 (Experiment 1) and CH3CN (Experiment 2) ices. In addition, we have also irradiated H2O:c-C6H6:CH3CN (Experiments 7 and 8), and CO:c-C6H6:CH3CN (Experiments 9 and 10) ice mixtures with both, 2 keV electrons (Experiments 7 and 9) and Ly-alpha photons (Experiments 8 and 10). 

The results of these experiments are presented in