title: Probing local and electronic structure in Warm Dense Matter: single pulse synchrotron x-ray absorption spectroscopy on shocked Fe.
abstract: Understanding Warm Dense Matter (WDM), the state of planetary interiors, is a new frontier in scientific research. There exists very little experimental data probing WDM states at the atomic level to test current models and those performed up to now are limited in quality. Here, we report a proof-of-principle experiment that makes microscopic investigations of materials under dynamic compression easily accessible to users and with data quality close to that achievable at ambient. Using a single 100 ps synchrotron x-ray pulse, we have measured, by K-edge absorption spectroscopy, ns-lived equilibrium states of WDM Fe. Structural and electronic changes in Fe are clearly observed for the first time at such extreme conditions. The amplitude of the EXAFS oscillations persists up to 500 GPa and 17000 K, suggesting an enduring local order. Moreover, a discrepancy exists with respect to theoretical calculations in the value of the energy shift of the absorption onset and so this comparison should help to refine the approximations used in models.
authors.affiliation: CEA, DAM, DIF, F-91297, Arpajon, France.|ESRF-The European Synchrotron 71, Avenue des Martyrs Grenoble, France.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Torchio
authors.affiliation: CEA, DAM, DIF, F-91297, Arpajon, France.
authors.forename: Florent
authors.initials: F
authors.lastname: Occelli
authors.affiliation: ESRF-The European Synchrotron 71, Avenue des Martyrs Grenoble, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Mathon
authors.affiliation: CEA, DAM, DIF, F-91297, Arpajon, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Sollier
authors.affiliation: CEA, DAM, DIF, F-91297, Arpajon, France.
authors.forename: Emilien
authors.initials: E
authors.lastname: Lescoute
authors.affiliation: CEA, DAM, DIF, F-91297, Arpajon, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Videau
authors.affiliation: LULI - CNRS, Ecole Polytechnique, CEA: Université Paris-Saclay, France.|UPMC Univ Paris 06:Sorbonne Universités - F-91128 Palaiseau cedex, France.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Vinci
authors.affiliation: LULI - CNRS, Ecole Polytechnique, CEA: Université Paris-Saclay, France.|UPMC Univ Paris 06:Sorbonne Universités - F-91128 Palaiseau cedex, France.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Benuzzi-Mounaix
authors.affiliation: Science and Technology Facilities Council, Daresbury Laboratory Sci-Tech Daresbury, Warrington WA4 4AD, UK.
authors.forename: Jon
authors.initials: J
authors.lastname: Headspith
authors.affiliation: Science and Technology Facilities Council, Daresbury Laboratory Sci-Tech Daresbury, Warrington WA4 4AD, UK.
authors.forename: William
authors.initials: W
authors.lastname: Helsby
authors.affiliation: Institute of Shock Physics, Imperial College London, London SW7 2AZ, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Bland
authors.affiliation: Science and Technology Facilities Council, Daresbury Laboratory Sci-Tech Daresbury, Warrington WA4 4AD, UK.|Institute of Shock Physics, Imperial College London, London SW7 2AZ, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Eakins
authors.affiliation: Institute of Shock Physics, Imperial College London, London SW7 2AZ, UK.
authors.forename: David
authors.initials: D
authors.lastname: Chapman
authors.affiliation: ESRF-The European Synchrotron 71, Avenue des Martyrs Grenoble, France.
authors.forename: Sakura
authors.initials: S
authors.lastname: Pascarelli
authors.affiliation: CEA, DAM, DIF, F-91297, Arpajon, France.
authors.forename: Paul
authors.initials: P
authors.lastname: Loubeyre