Abstract
Phenylalanine (Phe) is an amino acid that has been identified in carbonaceous meteorites; its formation mechanism in space is unknown, and its radioresistance has been the subject of investigation. This work aims at studying, in the laboratory, the Phe radiolysis by cosmic analogues. The Phe destruction rate, at 300 K, is measured for H, He, and N ion beam irradiation in the 0.5 to 2 kinetic MeV range. Fourier transform infrared (FTIR) spectroscopy was employed to monitor the molecular degradation as a function of fluence. The Phe apparent destruction cross–section, σ
ap
d
, which includes radiolysis and sputtering processes, is determined to be proportional to the electronic stopping power, Se
. The measured parameter D
0 = 14.3 ± 2.2 eV/molec in the relationship, and
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