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arXiv · 1502.02721

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

P. A. Gerakines·R. L. Hudson·M. H. Moore·J. -L. Bell
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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.

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P. A. Gerakines, R. L. Hudson, M. H. Moore, J. -L. Bell. 2015-02-09. In-situ measurements of the radiation stability of amino acids at 15-140 K. https://doi.org/10.1016/j.icarus.2012.06.001

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