Organisers

• Thomas Niehaus (University of Bremen, Bremen Center for Computational Materials Science)
• Massimo Altarellli (European X-Ray Laser Project (XFEL), DESY Hamburg)
• Angel Rubio (Universidad del País Vasco)

Supports

   CECAM

Description

Ultra-bright short (<100 fs) pulses of spatially coherent x-ray radiation are expected to produce a variety of results in atomic, molecular, condensed matter and soft-condensed matter science; a partial realization of this promise is already evident from FLASH experiments. Results on ultra-high intensities photoionization of atoms already offer puzzling results [1] and the same is true for clusters [2]; novel techniques emerge for diffraction imaging [3].

The progress towards wavelengths comparable to interatomic distances opens the way to ultrafast structural studies, where atomic motions during photoinduced reactions or phase transformations can be achieved by pump-probe techniques. Early attempts using presently existing sources show the wealth of information and the potential to explore Franck Condon diagrams directly, accessing regions of conical intersections and non-adiabatic regimes [4,5]

Scientific Objectives

Computational modelling of these phenomena will require the transformation of current simulation methods including adaptation to the next generation of high-performance computers, and the development of entirely new methods to address the challenges of energy, length and time-scales thrown open by new experimental techniques.

Computational science based on atomistic models has had a tremendous impact over the past few years. Maintaining this progress will require challenges on several fronts to be addressed simultaneously; new and more complex measurements from the new generation of facilities, new phenomena on different length and timescales and new developments in high performance computing technology.

The purpose of this workshop is to identify some of the "grand challenge problems" in experiment-facing computational science which will require action on a European scale and which will require the expertise of experiment and theory.

References

[1] A. A. Sorokin, S. V. Bobashev, T. Feigl, K. Tiedtke, H. Wabnitz, and M. Richter,
Photoelectric Effect at Ultrahigh Intensities, Phys. Rev. Lett. 99, 213002 (2007)
[2] C. Bostedt, H. Thomas, M. Hoener, E. Eremina, T. Fennel, K.-H. Meiwes-Broer, H. Wabnitz, M. Kuhlmann, E. Plönjes, K. Tiedtke, R. Treusch, J. Feldhaus, A.R.B. de Castro and T. Möller, Multistep Ionization of Argon Clusters in intense femtosecond XUV pulses, Phys. Rev. Lett. 100, 133401 (2008)
[3] Henry N. Chapman, Stefan P. Hau-Riege, Michael J. Bogan, Saša Bajt, Anton Barty, Sébastien Boutet, Stefano Marchesini, Matthias Frank, Bruce W. Woods, W. Henry Benner, Richard A. London, Urs Rohner, Abraham Szöke, Eberhard Spiller, Thomas Möller, Christoph Bostedt, David A. Shapiro, Marion Kuhlmann, Rolf Treusch, Elke Plönjes, Florian Burmeister, Magnus Bergh, Calle Caleman, Gösta Huldt, M. Marvin Seibert, and Janos Hajdu, Femtosecond Time-Delay X-ray Holography, Nature 448, 676-679 (2007)
[4] Matteo Rini, Andrea Cavalleri, Robert W. Schoenlein, René López, Leonard C. Feldman, Richard F. Haglund, Jr., Lynn A. Boatner, and Tony E. Haynes, Photoinduced phase transition in VO2 nanocrystals: ultrafast control of surface-plasmon resonance, Optics Letters 30, 558 (2005)
[5] A M Lindenberg, J Larsson, K Sokolowski-Tinten, K J Gaffney, C Blome, O Synnergren, J Sheppard, C Caleman, A G Macphee, D Weinstein, D P Lowney, T K Allison, T Matthews, R W Falcone, A L Cavalieri, D M Fritz, S H Lee, P H Bucksbaum, D A Reis, J Rudati, P H Fuoss, C C Kao, D P Siddons, R Pahl, J Als-Nielsen, S Duesterer, R Ischebeck, H Schlarb, H Schulte-Schrepping, Th Tschentscher, J Schneider, D von der Linde, O Hignette, F Sette, H N Chapman, R W Lee, T N Hansen, S Techert, J S Wark, M Bergh, G Huldt, D van der Spoel, N Timneanu, J Hajdu, R A Akre, E Bong, P Krejcik, J Arthur, S Brennan, K Luening, J B Hastings, Atomic Scale Visualization of Inertial Dynamics, Science, 308, 392 (2005)