TY - JOUR A1 - Beye, Martin A1 - Öberg, Henrik A1 - Xin, Hongliang A1 - Dakovski, Georgi L. A1 - Föhlisch, Alexander A1 - Gladh, Jorgen A1 - Hantschmann, Markus A1 - Hieke, Florian A1 - Kaya, Sarp A1 - Kühn, Danilo A1 - LaRue, Jerry A1 - Mercurio, Giuseppe A1 - Minitti, Michael P. A1 - Mitra, Ankush A1 - Moeller, Stefan P. A1 - Ng, May Ling A1 - Nilsson, Anders A1 - Nordlund, Dennis A1 - Norskov, Jens A1 - Öström, Henrik A1 - Ogasawara, Hirohito A1 - Persson, Mats A1 - Schlotter, William F. A1 - Sellberg, Jonas A. A1 - Wolf, Martin A1 - Abild-Pedersen, Frank A1 - Pettersson, Lars G. M. A1 - Wurth, Wilfried T1 - Chemical Bond Activation Observed with an X-ray Laser JF - The journal of physical chemistry letters N2 - The concept of bonding and antibonding orbitals is fundamental in chemistry. The population of those orbitals and the energetic difference between the two reflect the strength of the bonding interaction. Weakening the bond is expected to reduce this energetic splitting, but the transient character of bond-activation has so far prohibited direct experimental access. Here we apply time-resolved soft X-ray spectroscopy at a free electron laser to directly observe the decreased bonding antibonding splitting following bond-activation using an ultrashort optical laser pulse. Y1 - 2016 U6 - https://doi.org/10.1021/acs.jpclett.6b01543 SN - 1948-7185 VL - 7 SP - 3647 EP - 3651 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Kroll, Thomas A1 - Kern, Jan A1 - Kubin, Markus A1 - Ratner, Daniel A1 - Gul, Sheraz A1 - Fuller, Franklin D. A1 - Löchel, Heike A1 - Krzywinski, Jacek A1 - Lutman, Alberto A1 - Ding, Yuantao A1 - Dakovski, Georgi L. A1 - Moeller, Stefan A1 - Turner, Joshua J. A1 - Alonso-Mori, Roberto A1 - Nordlund, Dennis L. A1 - Rehanek, Jens A1 - Weniger, Christian A1 - Firsov, Alexander A1 - Brzhezinskaya, Maria A1 - Chatterjee, Ruchira A1 - Lassalle-Kaiser, Benedikt A1 - Sierra, Raymond G. A1 - Laksmono, Hartawan A1 - Hill, Ethan A1 - Borovik, Andrew S. A1 - Erko, Alexei A1 - Föhlisch, Alexander A1 - Mitzner, Rolf A1 - Yachandra, Vittal K. A1 - Yano, Junko A1 - Wernet, Philippe A1 - Bergmann, Uwe T1 - X-ray absorption spectroscopy using a self-seeded soft X-ray free-electron laser JF - Optics express : the international electronic journal of optics N2 - X-ray free electron lasers (XFELs) enable unprecedented new ways to study the electronic structure and dynamics of transition metal systems. L-edge absorption spectroscopy is a powerful technique for such studies and the feasibility of this method at XFELs for solutions and solids has been demonstrated. However, the required x-ray bandwidth is an order of magnitude narrower than that of self-amplified spontaneous emission (SASE), and additional monochromatization is needed. Here we compare L-edge x-ray absorption spectroscopy (XAS) of a prototypical transition metal system based on monochromatizing the SASE radiation of the linac coherent light source (LCLS) with a new technique based on self-seeding of LCLS. We demonstrate how L-edge XAS can be performed using the self-seeding scheme without the need of an additional beam line monochromator. We show how the spectral shape and pulse energy depend on the undulator setup and how this affects the x-ray spectroscopy measurements. (C) 2016 Optical Society of America Y1 - 2016 U6 - https://doi.org/10.1364/OE.24.022469 SN - 1094-4087 VL - 24 SP - 22469 EP - 22480 PB - Optical Society of America CY - Washington ER -