Photoelectron Diffraction Imaging of a Molecular Breakup Using an X-Ray Free-Electron Laser
Gregor Kastirke, M. S. Schöffler, M. Weller, J. Rist, Rebecca Boll, N. Anders, T. Baumann, S. Eckart, Benjamin Erk, A. De Fanis, K. Fehre, Averell Gatton, Sven Grundmann, Patrik Grychtol, Alexander Hartung, M. Hofmann, Markus Ilchen, Christian Jänke, M. Kircher, M. Kunitski, Xiang Li, Tommaso Mazza, N. Melzer, J. Montaño, Valerija Music, G. Nalin, Yevheniy Ovcharenko, A. Pier, Nils Rennhack, Daniel E. Rivas, R. Dörner, Daniel Rolles, Artem Rudenko, Philipp Schmidt, J. Siebert, N. Strenger, D. Trabert, Isabel Vela-Pérez, R. Wagner, Th. Weber, Joshua Williams, Paweł Ziółkowski, Lothar Schmidt, A. Czasch, Florian Trinter, Michael Meyer, Kiyoshi Ueda, Philipp V. Demekhin, T. Jahnke
Abstract
A central motivation for the development of x-ray free-electron lasers has been the prospect of timeresolved single-molecule imaging with atomic resolution. Here, we show that x-ray photoelectron diffraction-where a photoelectron emitted after x-ray absorption illuminates the molecular structure from within-can be used to image the increase of the internuclear distance during the x-ray-induced fragmentation of an O 2 molecule. By measuring the molecular-frame photoelectron emission patterns for a two-photon sequential K-shell ionization in coincidence with the fragment ions, and by sorting the data as a function of the measured kinetic energy release, we can resolve the elongation of the molecular bond by approximately 1.2 a.u. within the duration of the x-ray pulse. The experiment paves the road toward timeresolved pump-probe photoelectron diffraction imaging at high-repetition-rate x-ray free-electron lasers.