Ultrafast inter-ionic charge transfer of transition-metal complexes mapped by femtosecond X-ray powder diffraction

Journal Article · Sun Apr 14 00:00:00 EDT 2013 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4800223· OSTI ID:22105475

Freyer, Benjamin; Zamponi, Flavio; Juve, Vincent; Stingl, Johannes; Woerner, Michael; Elsaesser, Thomas ^[1]; Chergui, Majed ^[2]

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1. Max-Born-Institut fuer Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2 A, 12489 Berlin (Germany)
2. Ecole Polytechnique Federale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, Faculte des Sciences de Base, ISIC-BSP, CH-1015 Lausanne (Switzerland)

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){sub 3}]{sup 2+}) complexes and their PF{sub 6}{sup -} 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){sub 3}]{sup 2+} 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 PF{sub 6}{sup -} 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.

• OSTI ID: 22105475
• Journal Information: Journal of Chemical Physics, Vol. 138, Issue 14; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE
BIPYRIDINES
CHARGE EXCHANGE
COMPLEXES
CRYSTAL STRUCTURE
ELECTRON DENSITY
ELECTRONIC STRUCTURE
EXCITATION
IONIC CRYSTALS
IRON COMPOUNDS
MANY-BODY PROBLEM
MOLECULAR STRUCTURE
MULTI-PHOTON PROCESSES
PHOTONS
POLARONS
SPATIAL RESOLUTION
TRANSITION ELEMENTS
X-RAY DIFFRACTION