SPP 1134:  Transient structures in condensed matter investigated by ultrafast x-ray techniques

• Subject Area: Physics
• Term: from 2002 to 2008
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5471573

The priority programme is devoted to ultrafast structural changes in condensed matter which are studied by ultrafast x-ray techniques. The generation and characterization of ultrashort hard x-ray pulses are being combined with detecting and analyzing processes of structural change by x-ray diffraction and absorption. This research aims at a basic understanding of the relevant nonequilibrium processes occurring on a time scale between 10 fs and 10 ps and the underlying microsopic mechanisms. In this way, relationships between structure and function of the systems investigated will be elucidated.Photoinduced ultrafast phase transitions, e.g., from the solid to the liquid phase and/or between different crystalline structures, as well as the dynamics of crystal lattices, e.g., the propagation of phonon wave packets or shock waves, are studied in metals, semiconductors, and semiconductor nanostructures. Reversible or irreversible changes of atomic position are directly monitored by time-resolved x-ray diffraction. Such experiments are combined with theoretical simulations of the microscopic structural changes. In crystallized macromolecules, i.e. biopolymers, chromopeptides and proteins, elementary steps of (bio)chemical reactions are studied, in disordered systems, e.g., the liquid phase, transient structures under the influence of the environment. Research on laser based compact sources for ultrashort x-ray pulses and new concepts for x-ray targets and optical components represents an important aspect of this work which is worked on in close collaboration of the groups participating in the priority programme.

• DFG Programme: Priority Programmes

Projects

• Characterization of hydrogen bonded transients in liquid water and ice by ultrafast infrared pump and x-ray absorption probe spectroscopy (Applicant Wernet, Philippe )
• Femtosecond laser-excited phase transitions and shock waves studied with ultrafast time-resolved X-ray diffraction (Applicant Sokolowski-Tinten, Klaus )
• Four-dimensional (spatial and temporal) investigation of hard x-ray emission produced by intense femtosecond laser interactions with solid targets (Applicants Gibbon, Paul ;  Teubner, Ulrich )
• Generation, diagnostics, and optimization of keV X-ray-pulses with a high-power sub-10-fs-laser (Applicant Pretzler, Georg )
• Investigation of fast processes in condensed matter by time resolved x-ray diffraction (Applicant Uschmann, Ingo )
• Investigation of transient structures of photo-induced chemical reactions in solution with ultrafast XUV-photoelectron spectroscopy (Applicant Abel, Bernd )
• Investigation of ultrafast structural changes of metallic layers and metallo-organic complexes by hard x-ray photoemission and diffraction (Applicant Zacharias, Helmut )
• Optimization and first applications of a compact, high-repetition rate, ultrashort hard-x-ray and electron source based on the combination of femtosecond lasers with an x-ray diode (Applicant Chichkov, Boris )
• Optimization and first applications of a compact, high-repetition rate, ultrashort hard-x-ray and electron source based on the combination of femtosecond lasers with an x-ray diode (Applicant Baumert, Thomas )
• Reversible structural changes of crystalline solids studied by ultrafast x-ray diffraction (Applicant Wörner, Michael )
• Structural relaxation of hydrogen bonded systems investigated by time-resolved X-ray diffraction (Applicant Laubereau, Alfred )
• Time-dependent diffraction and EXAFS during laser induced ultrashort structural changes: theory and simulations (Applicant Garcia, Martin Ezequiel )
• Towards new regimes of lattice dynamics using femtosecond time-resolved x-ray scattering (Applicant von der Linde, Dietrich )
• Transient structures in condensed matter investigated by ultrafast x-ray techniques (Applicant Elsässer, Thomas )
• X-ray diffraction experiments on ultrafast photo-chemical reactions in solid state and solution with regard to biological applications (Applicant Zinth, Wolfgang )
• X-ray spectroscopy with high temporal and spatial resolution (Applicant Spielmann, Christian )

• Spokesperson: Professor Dr. Thomas Elsässer