20-EPN-032: Radioresistance of aromatic complex organic molecules
September 5, 2021

20-EPN-032: Radioresistance of aromatic complex organic molecules: nucleobases.

Virtual visit by Hermann Rothard, CIMAP (Caen, F) CNRS (France) to TA2.11 Atomki Ice Chamber for Astrophysics / Astrochemistry (ICA) (Hungary).
Dates of visit: 17 May – 02 July 2021

Report Summary: Complex molecules (including amino acids and nucleobases) can be formed in cold space environments conditions (e.g. dense molecular clouds, outer solar system) by e.g. UV irradiation and ion bombardment of ices containing simple molecules. Consequently, the radiation resistance of such complex molecules in order to determine their survival times in space should be investigated. We therefore studied the radiolysis and radio-resistance of the purine nucleobase (Adenine, two aromatic rings) in solid phase as a function of temperature (20-300 K) with H (0.8 MeV) and He (3.2 MeV) beams at ATOMKI. This first systematic study of the influence of the temperature revealed that Adenine is found to be significantly (of the order of 50%) more radio-resistant at high temperatures. At low temperatures T < 50K, Adenine is more radiosensitive (higher cross sections).

The results are preliminary and analysis is ongoing. Furthermore, we found that the destruction cross sections scales with the electronic stopping stopping following a power law with a stronger than linear dependence.

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