TY - JOUR AU - Milne, Chris J AU - Pham, Van-Thai AU - Gawelda, Wojciech AU - Van der Veen, Renske M AU - El Nahhas, Amal AU - Johnson, Steven L AU - Beaud, Paul AU - Ingold, Gerhard AU - Lima, Frederico AU - Vithanage, Dimali A AU - Benfatto, Maurizio AU - Grolimund, Daniel AU - Borca, Camelia AU - Kaiser, Maik AU - Hauser, Andreas AU - Abela, Rafael AU - Bressler, Christian AU - Chergui, Majed TI - Time-resolved x-ray absorption spectroscopy: Watching atoms dance PY - 2009 JF - Journal of Physics: Conference Series JA - J. Phys. VL - 190 SP - 12052 L1 - http://iopscience.iop.org/article/10.1088/1742-6596/190/1/012052/pdf L3 - http://stacks.iop.org/1742-6596/190/i=1/a=012052?key=crossref.5c814f915db286311bf4d7e5c1fe643e M3 - 10.1088/1742-6596/190/1/012052 UR - http://dx.doi.org/10.1088/1742-6596/190/1/012052 N2 - The introduction of pump-probe techniques to the field of x-ray absorption spectroscopy (XAS) has allowed the monitoring of both structural and electronic dynamics of disordered systems in the condensed phase with unprecedented accuracy, both in time and in space. We present results on the electronically excited high-spin state structure of an Fe(II) molecular species, [FeII(bpy)3]2+, in aqueous solution, resolving the Fe-N bond distance elongation as 0.2 Å. In addition an analysis technique using the reduced χ2 goodness of fit between FEFF EXAFS simulations and the experimental transient absorption signal in energy space has been successfully tested as a function of excited state population and chemical shift, demonstrating its applicability in situations where the fractional excited state population cannot be determined through other measurements. Finally by using a novel ultrafast hard x-ray \'slicing\' source the question of how the molecule relaxes after optical excitation has been successfully resolved using femtosecond XANES. ID - 1604 ER -