Vibrational wavepacket dynamics in Fe carbene photosensitizer determined with femtosecond X-ray emission and scattering

Research output: Contribution to journalArticle


The non-equilibrium dynamics of electrons and nuclei govern the function of photoactive materials. Disentangling these dynamics remains a critical goal for understanding photoactive materials. Here we investigate the photoinduced dynamics of the [Fe(bmip)2]2+ photosensitizer, where bmip = 2,6-bis(3-methyl-imidazole-1-ylidine)-pyridine, with simultaneous femtosecond-resolution Fe Kα and Kβ X-ray emission spectroscopy (XES) and X-ray solution scattering (XSS). This measurement shows temporal oscillations in the XES and XSS difference signals with the same 278 fs period oscillation. These oscillations originate from an Fe-ligand stretching vibrational wavepacket on a triplet metal-centered (3MC) excited state surface. This 3MC state is populated with a 110 fs time constant by 40% of the excited molecules while the rest relax to a 3MLCT excited state. The sensitivity of the Kα XES to molecular structure results from a 0.7% average Fe-ligand bond length shift between the 1 s and 2p core-ionized states surfaces.


  • Kristjan Kunnus
  • Morgane Vacher
  • Tobias C.B. Harlang
  • Kasper S. Kjær
  • Kristoffer Haldrup
  • Elisa Biasin
  • Tim B. van Driel
  • Mátyás Pápai
  • Yizhu Liu
  • Hideyuki Tatsuno
  • Cornelia Timm
  • Erik Källman
  • Mickaël Delcey
  • Robert W. Hartsock
  • Marco E. Reinhard
  • Sergey Koroidov
  • Mads G. Laursen
  • Frederik B. Hansen
  • Peter Vester
  • Morten Christensen
  • Lise Sandberg
  • Zoltán Németh
  • Dorottya Sárosiné Szemes
  • Éva Bajnóczi
  • Roberto Alonso-Mori
  • James M. Glownia
  • Silke Nelson
  • Marcin Sikorski
  • Dimosthenis Sokaras
  • Henrik T. Lemke
  • Sophie E. Canton
  • Klaus B. Møller
  • Martin M. Nielsen
  • György Vankó
  • Marcus Lundberg
  • Kelly J. Gaffney
External organisations
  • Stanford Linear Accelerator Center (SLAC)
  • Uppsala University
  • Technical University of Denmark
  • Lund University
  • Niels Bohr Institute
  • Wigner Research Centre for Physics, Hungarian Academy of Sciences
  • ELI-HU Non-profit Ltd
  • German Electron Synchrotron (DESY)
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Atom and Molecular Physics and Optics
Original languageEnglish
Article number634
JournalNature Communications
Publication statusPublished - 2020 Jan 31
Publication categoryResearch