Heidelberg 2015 – scientific programme
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MO: Fachverband Molekülphysik
MO 17: Cold Molecules 3
MO 17.6: Talk
Thursday, March 26, 2015, 12:30–12:45, PH/HS1
X-ray diffraction off isolated laser-aligned gas-phase molecules — •Thomas Kierspel1,2, Fenglin Wang1,3, and Jochen Küpper1,2,4 — 1Center for Free-Electron Laser Science, DESY, Hamburg, Germany — 2The Hamburg Center for Ultrafast Imaging, University of Hamburg, Germany — 3PULSE Institute, Stanford University, Stanford, California, USA — 4Department of Physics, University of Hamburg, Germany
We report on x-ray diffraction off aligned isolated 2,5-diiodothiophene molecules. Using 0.13 nm (9.5 keV) radiation diffraction patters were recorded at a degree of alignment of <cos2θ>≈0.85. The short wavelength provides atomic resolution information of the molecular structure. The estimated 0.1 scattered photons/shot are mainly due to the two-center interference of the two iodines [1], with secondary signals due to the sulphur atom in the ring.
The main challenge of this experiment is the low signal-to-noise level. The experimental background is estimated to be more than 10 photons/shot, but should be largely discriminable due to photon energy differences. We discuss strategies on how to overcome the low signal-to-noise level and present resolutions by means of data analysis.
This work was carried out in a collaboration with spokespersons F. Wang, J. Küpper, P. Bucksbaum, and H. Chapman. The collaboration consists of CFEL, PULSE, LCLS, European XFEL, Aarhus University, Kansas State University, Stanford University, and Uppsala University. LCLS is operated by Stanford University on behalf of the US DOE.
[1] Küpper et al., Phys. Rev. Lett. 122, 083002 (2014)