Water is a radiation protection agent for ionised pyrrole

Melby Johny; Constant A. Schouder; Ahmed Al-Refaie; Lanhai He; Joss Wiese; Henrik Stapelfeldt; Sebastian Trippel; Jochen Küpper

arXiv · 2010.00453

Water is a radiation protection agent for ionised pyrrole

Melby Johny·Constant A. Schouder·Ahmed Al-Refaie·Lanhai He·Joss Wiese·Henrik Stapelfeldt·Sebastian Trippel·Jochen Küpper

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Abstract

Radiation-induced damage of biological matter is an ubiquitous problem in nature. The influence of the hydration environment is widely discussed, but its exact role remains elusive. Utilising well defined solvated-molecule aggregates, we experimentally observed a hydrogen-bonded water molecule acting as a radiation protection agent for ionised pyrrole, a prototypical aromatic biomolecule. Pure samples of pyrrole and pyrrole(H$_2$O) were outer-valence ionised and the subsequent damage and relaxation processes were studied. Bare pyrrole ions fragmented through the breaking of C-C or N-C covalent bonds. However, for pyrrole(H$_2$O)$^+$, we observed a strong protection of the pyrrole ring through the dissociative release of neutral water or by transferring an electron or proton across the hydrogen bond. Overall, a single water molecule strongly reduces the fragmentation probability and thus the persistent radiation damage of singly-ionised pyrrole.

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Melby Johny, Constant A. Schouder, Ahmed Al-Refaie, Lanhai He, Joss Wiese, Henrik Stapelfeldt, Sebastian Trippel, Jochen Küpper. 2020-10-01. Water is a radiation protection agent for ionised pyrrole. https://arxiv.org/abs/2010.00453

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