Ultrafast dynamics of a nucleobase analogue illuminated by a short intense x-ray free electron laser pulse

K. Nagaya, Koji Motomura, E. Kukk, Hironobu Fukuzawa, S. Wada, T. Tachibana, Y. Ito, S. Mondal, T. Sakai, K. Matsunami, R. Koga, S. Ohmura, Y. Takahashi, M. Kanno, A. Rudenko, C. Nicolas, X. J. Liu, Y. Zhang, J. Chen, M. AnandY. H. Jiang, D. E. Kim, K. Tono, M. Yabashi, Hirohiko Kono, C. Miron, M. Yao, Kiyoshi Ueda

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


Understanding 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 singleshot molecular imaging as a consistent approach, provided the radiation pulse used is brief enough.

Original languageEnglish
Article number021035
JournalPhysical Review X
Issue number2
Publication statusPublished - 2016

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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