TY - JOUR A1 - Pontius, N. A1 - Kachel, T. A1 - Schüssler-Langeheine, C. A1 - Schlotter, W. F. A1 - Beye, Martin A1 - Sorgenfrei, Florian A1 - Chang, C. F. A1 - Föhlisch, Alexander A1 - Wurth, W. A1 - Metcalf, P. A1 - Leonov, I. A1 - Yaresko, A. A1 - Stojanovic, N. A1 - Berglund, Martin A1 - Guerassimova, N. A1 - Duesterer, S. A1 - Redlin, H. A1 - Duerr, H. A. T1 - Time-resolved resonant soft x-ray diffraction with free-electron lasers femtosecond dynamics across the Verwey transition in magnetite JF - Applied physics letters N2 - Resonant soft x-ray diffraction (RSXD) with femtosecond (fs) time resolution is a powerful tool for disentangling the interplay between different degrees of freedom in strongly correlated electron materials. It allows addressing the coupling of particular degrees of freedom upon an external selective perturbation, e. g., by an optical or infrared laser pulse. Here, we report a time-resolved RSXD experiment from the prototypical correlated electron material magnetite using soft x-ray pulses from the free-electron laser FLASH in Hamburg. We observe ultrafast melting of the charge-orbital order leading to the formation of a transient phase, which has not been observed in equilibrium. Y1 - 2011 U6 - https://doi.org/10.1063/1.3584855 SN - 0003-6951 VL - 98 IS - 18 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Sun, Y. -P. A1 - Hennies, Franz A1 - Pietzsch, Annette A1 - Kennedy, B. A1 - Schmitt, Thorsten A1 - Strocov, Vladimir N. A1 - Andersson, Joakim A1 - Berglund, Martin A1 - Rubensson, Jan-Erik A1 - Aidas, K. A1 - Gel'mukhanov, F. A1 - Odelius, Michael A1 - Föhlisch, Alexander T1 - Intramolecular soft modes and intermolecular interactions in liquid acetone JF - Physical review : B, Condensed matter and materials physics N2 - Resonant inelastic x-ray scattering spectra excited at the O1s(-1)pi* resonance of liquid acetone are presented. Scattering to the electronic ground state shows a resolved vibrational progression where the dominant contribution is due to the C-O stretching mode, thus demonstrating a unique sensitivity of the method to the local potential energy surface in complex molecular systems. For scattering to electronically excited states, soft vibrational modes and, to a smaller extent, intermolecular interactions give a broadening, which blurs the vibrational fine structure. It is predicted that environmental broadening is dominant in aqueous acetone. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevB.84.132202 SN - 1098-0121 VL - 84 IS - 13 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Hennies, Franz A1 - Pietzsch, Annette A1 - Berglund, Martin A1 - Föhlisch, Alexander A1 - Schmitt, Thorsten A1 - Strocov, Vladimir A1 - Karlsson, Hans O. A1 - Andersson, Joakim A1 - Rubensson, Jan-Erik T1 - Resonant inelastic scattering spectra of free molecules with vibrational resolution N2 - Inelastic x-ray scattering spectra excited at the 1s(-1) pi* resonance of gas phase O-2 have been recorded with an overall energy resolution that allows for well-resolved vibrational progressions. The nuclear wave packet dynamics in the intermediate state is reflected in vibrational excitations of the electronic ground state, and by fine-tuning the excitation energy the dissociation dynamics in the predissociative B' (3) Pi(g) final state is controlled. Y1 - 2010 UR - http://prl.aps.org/ U6 - https://doi.org/10.1103/Physrevlett.104.193002 SN - 0031-9007 ER -