2013-06-19 01:37:21 876 W. Gawelda, V. T. Pham, A. El Nahhas, M. Kaiser, Y. Zaushitsyn, S. L. Johnson, D. Grolimund, R. Abela, A. Hauser, C. Bressler, M. Chergui Gawelda, W. Pham, V.T. El Nahhas, A. Kaiser, M. Zaushitsyn, Y. Johnson, S.L. Grolimund, D. Abela, R. Hauser, A. Bressler, C. Chergui, M. American Institute of Physics Conference Proceedings Am. Inst. Phys. Conf. Proc. 0094-243X 2007 882 31 36 H We describe an advanced setup for time-resolved x-ray absorption fine structure (XAFS) Spectroscopy with picosecond temporal resolution. It combines an intense femtosecond laser source synchronized to the x-ray pulses delivered into the microXAS beamline of the Swiss Light Source (SLS). The setup is applied to measure the short-lived high-spin geometric structure of photoexcited aqueous Fe(bpy)₃ at room temperature.

]]> 10.1063/1.2644425 4058 856 Wojciech Gawelda, Van-Thai Pham, Maurizio Benfatto, Yuri Zaushitsyn, Maik Kaiser, Daniel Grolimund, Steven L. Johnson, Rafael Abela, Andreas Hauser, Christian Bressler, Majed Chergui Gawelda, Wojciech Pham, Van-Thai Benfatto, Maurizio Zaushitsyn, Yuri Kaiser, Maik Grolimund, Daniel Johnson, Steven L. Abela, Rafael Hauser, Andreas Bressler, Christian Chergui, Majed Physical Review Letters Phys. Rev. Lett. 0031-9007 2007 98 57401 H Structural changes of the iron(II)-tris-bipyridine ([Fe^II(bpy)₃]²⁺) complex induced by ultrashort pulse excitation and population of its short-lived (≤0.6  ns) quintet high spin state have been detected by picosecond x-ray absorption spectroscopy. The structural relaxation from the high spin to the low spin state was followed over the entire lifetime of the excited state. A combined analysis of the x-ray-absorption near-edge structure and extended x-ray-absorption fine structure spectroscopy features delivers an Fe-N bond elongation of 0.2 Å in the quintet state compared to the singlet ground state.

]]> P418 10.1103/PhysRevLett.98.057401 3198 http://www.unige.ch/sciences/chifi/publis/refs_pdf/ref00856.pdf