20-EPN-025: Radioresistance of aromatic complex organic molecules
June 3, 2023

20-EPN-025: Radioresistance of aromatic complex organic molecules (nucleobases)

Virtual visit by Alicja Domaracka and Anna Bychkova, CIMAP-CNRS (France) to TA2.11 Atomki Ice Chamber for Astrophysics / Astrochemistry (ICA) (Hungary).
Dates of visit: 17-28 January 2022

Report Summary: Over the last decades it became clear that we live in a “molecular universe”. Carbon forms the basis of the majority of the molecular species that so far have been identified in space. Although small carbon-based molecules, like CO and CO2, are some of the most abundant molecules in space, only a small fraction of the carbon is expected to be locked up in such species. It was proposed that a large portion of the interstellar carbon, up to 20%, is built in polycyclic aromatic hydrocarbons (PAHs) and fullerenes. Several laboratory studies were carried out to investigate the effects of vacuum ultraviolet photolysis on PAH:H2O ices. However, data about interaction energetic ions with PAH ices are very scare.

We therefore studied the radiolysis of the pure pyrene ice and mixed pyrene- water ices at different concentrations at 20 K with 200 keV and 2 MeV H+ and 2 MeV C2+ beams at Atomki. The preliminary analysis of water-pyrene ices irradiated 200 keV H+ (with pyrene concentration from about 5 to 100% of pyrene) indicates that pyrene is more radio-resistant at high concentrations. The results are preliminary and analysis is ongoing.