• Kroll, T.; Kern, J.; Kubin, M.; Ratner, D.; Gul, S.; Fuller, F.; Löchel, H.; Krzywinski, J.; Lutman, A.; Ding, Y.; Dakovski, G.; Moeller, S.; Turner, J.; Alonso-Mori, R.; Nordlund, D.; Rehanek, J.; Weniger, C.; Firsov, A.; Brzhezinskaya, M.; Chatterjee, R.; Lassalle-Kaiser, B.; Sierra, R.; Laksmono, H.; Hill, E.; Borovik, A.; Erko, A.; Föhlisch, A.; Mitzner, R.; Yachandra, V.; Yano, J.; Wernet, P.; Bergmann, U.: X-ray absorption spectroscopy using a self-seeded soft X-ray free-electron laser. Optics Express 24 (2016), p. 22469-22480

Open Accesn Version

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.