Visualizing the non-equilibrium dynamics of photoinduced intramolecular electron transfer with femtosecond X-ray pulses

Ultrafast photoinduced electron transfer preceding energy equilibration still poses many experimental and conceptual challenges to the optimization of photoconversion since an atomic-scale description has so far been beyond reach. Here we combine femtosecond transient optical absorption spectroscopy with ultrafast X-ray emission spectroscopy and diffuse X-ray scattering at the SACLA facility to track the non-equilibrated electronic and structural dynamics within a bimetallic donor–acceptor complex that contains an optically dark centre.

Sophie E. Canton, Kasper S. Kjær, György Vankó, Tim B. van Driel, Shin-ichi Adachi, Amélie Bordage, Christian Bressler, Pavel Chabera, Morten Christensen, Asmus O. Dohn, Andreas Galler, Wojciech Gawelda, David Gosztola, Kristoffer Haldrup, Tobias Harlang, Yizhu Liu, Klaus B. Møller, Zoltán Németh, Shunsuke Nozawa, Mátyás Pápai, Tokushi Sato, Takahiro Sato, Karina Suarez-Alcantara, Tadashi Togashi, Kensuke Tono, Jens Uhlig, Dimali A. Vithanage, Kenneth Wärnmark, Makina Yabashi, Jianxin Zhang, Villy Sundström & Martin M. Nielsen.

Nature Communications 6, doi:10.1038/ncomms7359, Published 02 March 2015

Electron transfer 

Exploiting the 100-fold increase in temporal resolution as compared with storage ring facilities, these measurements constitute the first X-ray-based visualization of a non-equilibrated intramolecular electron transfer process over large interatomic distances. Experimental and theoretical results establish that mediation through electronically excited molecular states is a key mechanistic feature. The present study demonstrates the extensive potential of femtosecond X-ray techniques as diagnostics of non-adiabatic electron transfer processes in synthetic and biological systems, and some directions for future studies are outlined.




Martin Meedom Nielsen
DTU Physics
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