Berlin 2015 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 27: Posters: Complex Fluids and Soft Matter

BP 27.6: Poster

Dienstag, 17. März 2015, 14:00–16:00, Poster A

Microscopic structure of supercooled water studied by x-ray Compton scattering and x-ray Raman scattering — •Juri Nyrow¹, Felix Lehmkühler², Mikko Hakala³, Thomas Büning¹, Ingo Steinke², Christoph J. Sahle⁴, Karin Julius¹, Agnieszka Poulain⁴, Ali Al-Zein⁴, Thomas Buslaps⁴, Metin Tolan¹ und Christian Sternemann¹ — ¹Fakultät Physik/DELTA, TU Dortmund, GE-44221 Dortmund — ²Deutsches Elektronen-Synchrotron DESY, GE-22607 Hamburg — ³Department of Physics, University of Helsinki, FI-00014 Helsinki — ⁴ESRF, FR-38043 Grenoble Cedex 9

The microscopic structure of water at ambient and in supercooled conditions is controversially discussed, e.g. with respect to a mixture of low and high density water phases [1]. Recently, x-ray absorption and diffraction studies reported an increasing contribution of tetrahedrally coordinated low density water on cost of a highly disturbed hydrogen bonding network at supercooled conditions [2,3]. We investigated changes of the molecular structure in supercooled water for temperatures down to 255 K by x-ray Compton scattering and x-ray Raman scattering. The results indicate a strengthening of the tetrahedral hydrogen bond network, accompanied by a shortening of the intramolecular OH bond length upon supercooling. These findings will be discussed using structural models with different local bonding configurations [4].

[1] C. Huang et al. PNAS 106, 15214 (2009).

[2] J. A. Sellberg et al. J. Chem. Phys. 141, 034507 (2014).

[3] J. A. Sellberg et al. Nature 510 (7505), 381-384 (2014).

[4] M. Hakala et al. Phys. Rev. B 73, 035432 (2006).