title: X-ray imaging of chemically active valence electrons during a pericyclic reaction.
abstract: Time-resolved imaging of chemically active valence electron densities is a long-sought goal, as these electrons dictate the course of chemical reactions. However, X-ray scattering is always dominated by the core and inert valence electrons, making time-resolved X-ray imaging of chemically active valence electron densities extremely challenging. Here we demonstrate an effective and robust method, which emphasizes the information encoded in weakly scattered photons, to image chemically active valence electron densities. The degenerate Cope rearrangement of semibullvalene, a pericyclic reaction, is used as an example to visually illustrate our approach. Our work also provides experimental access to the long-standing problem of synchronous versus asynchronous bond formation and breaking during pericyclic reactions.
authors.affiliation: Max Born Institute, Max-Born-Strasse 2A, 12489 Berlin, Germany.
authors.forename: Timm
authors.initials: T
authors.lastname: Bredtmann
authors.affiliation: 1] Max Born Institute, Max-Born-Strasse 2A, 12489 Berlin, Germany [2] Blackett Laboratory, Imperial College London, London SW7 2AZ, UK.
authors.forename: Misha
authors.initials: M
authors.lastname: Ivanov
authors.affiliation: Max Born Institute, Max-Born-Strasse 2A, 12489 Berlin, Germany.
authors.forename: Gopal
authors.initials: G
authors.lastname: Dixit