In-situ measurements of the radiation stability of amino acids at 15-140 K

Abstract

We present new kinetics data on the radiolytic destruction of amino acids measured in situ with infrared spectroscopy. Samples were irradiated at 15, 100, and 140 K with 0.8-MeV protons, and amino-acid decay was followed at each temperature with and without H${}_2$O present. Observed radiation products included CO${}_2$ and amines, consistent with amino-acid decarboxylation. The half-lives of glycine, alanine, and phenylalanine were estimated for various extraterrestrial environments. Infrared spectral changes demonstrated the conversion from the non-zwitterion structure NH${}_2$-CH${}_2$(R)-COOH at 15 K to the zwitterion structure ${}^{+}$NH${}_3$-CH${}_2$(R)-COO${}^{-}$ at 140 K for each amino acid studied.

35 pages, 7 tables, 11 figures

References in corpus (1)

• The Distribution, Excitation and Formation of Cometary Molecules: Methanol, Methyl Cyanide and Ethylene Glycol

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