Schreck, S.; Beye, M.; Sellberg, J.A.; McQueen, T.; Laksmono, H.; Kennedy, B.; Eckert, S.; Schlesinger, D.; Nordlund, D.; Ogasawara, H.; Sierra, R.G.; Segtnan, V.H.; Kubicek, K.; Schlotter, W.F.; Dakovski, G.L.; Moeller, S.P.; Bergmann, U.; Techert, S.; Pettersson, L.G.M.; Wernet, P.; Bogan, M.J.; Harada, Y.; Nilsson, A.; Föhlisch, A.: Reabsorption of Soft X-Ray Emission at High X-Ray Free-Electron Laser Fluences. Physical Review Letters 113 (2014), p. 153002/1-6
10.1103/PhysRevLett.113.153002
Open Access Version
Abstract:
We report on oxygen K-edge soft x-ray emission spectroscopy from a liquid water jet at the Linac Coherent Light Source. We observe significant changes in the spectral content when tuning over a wide range of incident x-ray fluences. In addition the total emission yield decreases at high fluences. These modifications result from reabsorption of x-ray emission by valence-excited molecules generated by the Auger cascade. Our observations have major implications for future x-ray emission studies at intense x-ray sources. We highlight the importance of the x-ray pulse length with respect to the core-hole lifetime.