2025-03-10 ゲーテ大学
＜関連情報＞
- https://aktuelles.uni-frankfurt.de/english/x-ray-snapshot-how-light-bends-an-active-substance/
- https://www.nature.com/articles/s41467-025-57083-3
クーロン爆発イメージングによる2-チオウラシルの内部変換過程における超高速対称性低下の直接観察 Direct observation of ultrafast symmetry reduction during internal conversion of 2-thiouracil using Coulomb explosion imaging
Till Jahnke,Sebastian Mai,Surjendu Bhattacharyya,Keyu Chen,Rebecca Boll,Maria Elena Castellani,Simon Dold,Ulrike Frühling,Alice E. Green,Markus Ilchen,Rebecca Ingle,Gregor Kastirke,Huynh Van Sa Lam,Fabiano Lever,Dennis Mayer,Tommaso Mazza,Terence Mullins,Yevheniy Ovcharenko,Björn Senfftleben,Florian Trinter,Atia-Tul-Noor,Sergey Usenko,Anbu Selvam Venkatachalam,Artem Rudenko,… Markus Gühr
Nature Communications Published:28 February 2025
DOI:https://doi.org/10.1038/s41467-025-57083-3
Abstract
The photochemistry of heterocyclic molecules plays a decisive role for processes and applications like DNA photo-protection from UV damage and organic photocatalysis. The photochemical reactivity of heterocycles is determined by the redistribution of photoenergy into electronic and nuclear degrees of freedom, initially involving ultrafast internal conversion. Most heterocycles are planar in their ground state and internal conversion requires symmetry breaking. To lower the symmetry, the molecule must undergo an out-of-plane motion, which has not yet been observed directly. Here we show using the example of 2-thiouracil, how Coulomb explosion imaging can be utilized to extract comprehensive information on this molecular deformation, linking the extracted deplanarization of the molecular geometry to the previously studied temporal evolution of its electronic properties. Particularly, the protons of the exploded molecule are well-suited messengers carrying rich information on its geometry at distinct times after electronic excitation. We expect that our new analysis approach centered on these peripheral protons can be adapted as a general concept for future time-resolved studies of complex molecules in the gas phase.
