Nagaya, K.Motomura, K.Kukk, E.Fukuzawa, H.Wada, S.Tachibana, T.Ito, Y.Mondal, S.Sakai, T.Matsunami, K.Koga, R.Ohmura, S.Takahashi, Y.Kanno, M.Rudenko, ArtemNicolas, C.Liu, X. J.Zhang, Y.Chen, J.Anand, M.Jiang, Y. H.Kim, D. E.Tono, K.Yabashi, M.Kono, H.Miron, C.Yao, M.Ueda, K.2017-04-102017-04-102016-06-16http://hdl.handle.net/2097/35354Citation: Nagaya, K., Motomura, K., Kukk, E., Fukuzawa, H., Wada, S., Tachibana, T., . . . Ueda, K. (2016). Ultrafast Dynamics of a Nucleobase Analogue Illuminated by a Short Intense X-ray Free Electron Laser Pulse. Physical Review X, 6(2), 9. doi:10.1103/PhysRevX.6.021035Understanding x-ray radiation damage is a crucial issue for both medical applications of x rays and x-ray free-electron-laser (XFEL) science aimed at molecular imaging. Decrypting the charge and fragmentation dynamics of nucleobases, the smallest units of a macro-biomolecule, contributes to a bottom-up understanding of the damage via cascades of phenomena following x-ray exposure. We investigate experimentally and by numerical simulations the ultrafast radiation damage induced on a nucleobase analogue (5-iodouracil) by an ultrashort (10 fs) high-intensity radiation pulse generated by XFEL at SPring-8 Angstrom Compact free electron Laser (SACLA). The present study elucidates a plausible underlying radiosensitizing mechanism of 5-iodouracil. This mechanism is independent of the exact composition of 5-iodouracil and thus relevant to other such radiosensitizers. Furthermore, we found that despite a rapid increase of the net molecular charge in the presence of iodine, and of the ultrafast release of hydrogen, the other atoms are almost frozen within the 10-fs duration of the exposure. This validates single-shot molecular imaging as a consistent approach, provided the radiation pulse used is brief enough.Attribution 3.0 Unported (CC BY 3.0)https://creativecommons.org/licenses/by/3.0/IonizationChargeMoleculesOperationRegionAtomsArticle