Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of GraphSearch.
The transient electronic and molecular structure arising from photoinduced charge transfer in transition metal complexes is studied by X-ray powder diffraction with a 100 fs temporal and atomic spatial resolution. Crystals containing a dense array of Fe(II)-tris(bipyridine) (Fe(bpy)(3)) complexes and their PF6- counterions display pronounced changes of electron density that occur within the first 100 fs after two-photon excitation of a small fraction of the Fe(bpy)(3) complexes. Transient electron density maps derived from the diffraction data reveal a transfer of electronic charge from the Fe atoms and-so far unknown-from the PF6- counterions to the bipyridine units. Such charge transfer (CT) is connected with changes of the inter-ionic and the Fe-bipyridine distances. An analysis of the electron density maps demonstrates the many-body character of charge transfer which affects approximately 30 complexes around a directly photoexcited one. The many-body behavior is governed by the long-range Coulomb forces in the ionic crystals and described by the concept of electronic polarons. (C) 2013 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4800223]