Berlin 2014 – scientific programme

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MO: Fachverband Molekülphysik

MO 23: Femtosecond Spectroscopy 3

MO 23.7: Talk

Friday, March 21, 2014, 15:30–15:45, BEBEL HS213

Imaging valence electron motion during pericyclic reactions via time-resolved X-ray scattering — •Timm Bredmann, Mikhail Ivanov, and Gopal Dixit — Max-Born-Institut, Max-Born-Straße 2A, 12489 Berlin, Germany

Shooting the ultrashort, high-resolution movie of molecular processes is a long-standing dream of physicists, chemists and biologists, the realization of which will extend the understanding and hence the controlability of chemical reactions in synthesis and bioscience. Here, we show by means of quantum mechanical ab-initio simulations how time-resolved X-ray scattering can be used to achieve this goal. We introduce a new technique for reconstructing the electron density from the time-resolved scattering pattern using only information of weakly scattered photons, thereby filtering out major contributions of core and inert valence electrons, yielding direct insight into the making and breaking of chemical bonds in complex molecules. Taking the Cope rearrangement of semibullvalene as explicit example, we demonstrate that this technique provides direct experimental access to the long-standing problem of synchronous vs. asynchronous bond making and bond breaking in pericyclic reactions, which has solely been investigated theoretically up to date.