Berlin 2014 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 35: Poster: Interaction with VUV and X-ray light

A 35.2: Poster

Mittwoch, 19. März 2014, 16:30–18:30, Spree-Palais

Improving the orientation recovery using diffusion map — •Martin Winter, Ulf Saalmann, and Jan-Michael Rost — Max-Planck-Institut für Physik komplexer Systeme

Upcoming X-ray free electron lasers offer the potential of single-molecule coherent diffractive imaging without prior crystallization of the molecule. Since the molecules are in the gas phase, their orientations vary from shot to shot and the averaging of faint images from similar orientations requires a reliable orientation recovery of each image.

Here we show that such an orientation recovery using diffusion map [1] works only under certain conditions. We diagonalize the Laplace-Beltrami operator, which is approximated by diffusion map, for an ensembles of diffraction patterns from randomly orientated molecules and quantify the breakdown of the orientation recovery. For certain classes of molecules we improve the orientation recovery by hitting the molecule simultaneously from multiple directions or by using more eigenvectors from the diagonalization.

[1] Optics Express, Vol. 20, Issue 12, pp. 12799-12826 (2012)