论文标题
使用X射线自由电子激光器在光解过程中对离子手性碎片的位点特异性询问
Site-specific Interrogation of an Ionic Chiral Fragment During Photolysis Using an X-ray Free-Electron Laser
论文作者
论文摘要
具有高强度的超短脉冲的短波长自电子激光器已起源于从特定位点的远景跟踪分子动力学的新方法。 X射线泵X射线探针方案甚至允许使用“触发”事件来解决单个原子成分，该成分可以预言后续的分子动力学，同时能够以时间延迟的第二X射线脉冲选择性地探测演变的结构。在这里，我们使用线性极化的X射线光子来触发原型手性分子的光解，即三氟甲甲氧烷（C $ _3 $ _3 $ _3 $ _3 $ _3 $ f $ _3 $ o），在700 ev左右的Fluorine K-EDD上。然后，通过第二个圆极化的X射线脉冲探测富含氟的含氟的片段，以研究其立体化学敏感性的离子母体的化学移动内部壳电子。我们在实验上证明并在理论上支持具有极化控制的两色X射线泵X射线探针如何使Xfels成为手性识别的工具。
Short-wavelength free-electron lasers with their ultrashort pulses at high intensities have originated new approaches for tracking molecular dynamics from the vista of specific sites. X-ray pump X-ray probe schemes even allow to address individual atomic constituents with a 'trigger'-event that preludes the subsequent molecular dynamics while being able to selectively probe the evolving structure with a time-delayed second X-ray pulse. Here, we use a linearly polarized X-ray photon to trigger the photolysis of a prototypical chiral molecule, namely trifluoromethyloxirane (C$_3$H$_3$F$_3$O), at the fluorine K-edge at around 700 eV. The evolving fluorine-containing fragments are then probed by a second, circularly polarized X-ray pulse of higher photon energy in order to investigate the chemically shifted inner-shell electrons of the ionic motherfragment for their stereochemical sensitivity. We experimentally demonstrate and theoretically support how two-color X-ray pump X-ray probe experiments with polarization control enable XFELs as tools for chiral recognition.
