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                               “Structural dynamics of water using XFELs”





  Tuesday, 08 Sept 2020

    Video-Recording for any system with MP4-support

   - Video.mp4  (ca.241 Mb)


 13:00 – 13:45



Speaker today:    F. Perakis  (Stockholm University)




In this talk, an overview is given of our activities in probing water dynamics

using x-ray free electron lasers (XFELs). Specifically is discussed how coherent

x-rays allow to capture translational dynamics of water using X-ray Speckle

Visibility Spectroscopy (XSVS) [1] as well as orientational dynamics using X-ray

Optical Kerr Effect (OKE) Spectroscopy [2]. The results are compared to molecular

dynamics simulations which indicate the presence of cage effects in supercooled

water as well as the existence of two liquids, high- and low-density liquids

(HDL and LDL) with different polarisability.

Finally, here is also given a perspective of probing protein dynamics using these

techniques and open questions and challenges ahead are discussed [3].



[1] Coherent X-rays reveal the influence of cage effects on ultrafast water dynamics

F. Perakis, G. Camisasca, T.J. Lane, A. Späh, K.T. Wikfeldt, J.A. Sellberg, F. Lehmkühler, H. Pathak, K.H. Kim, K. Amann-Winkel, S. Schreck, S. Song, T. Sato, M. Sikorski, A. Eilert, T. McQueen, H. Ogasawara, D. Nordlund, W. Roseker, J. Koralek, S. Nelson, P. Hart, R. Alonso-Mori, Y. Feng, D. Zhu, A. Robert, G. Grübel, L.G.M. Pettersson, and A. Nilsson,

Nat. Commun. 9, 1917 (2018).




[2] Anisotropic X-Ray Scattering of Transiently Oriented Water

K.H. Kim, A. Späh, H. Pathak, C. Yang, S. Bonetti, K. Amann-Winkel, D. Mariedahl, D. Schlesinger, J.A. Sellberg, D. Mendez, G. van der Schot, H.Y. Hwang, J. Clark, O. Shigeki, T. Tadashi, Y. Harada, H. Ogasawara, T. Katayama, A. Nilsson, and F. Perakis,

Phys. Rev. Lett. 125, 076002 (2020).




[3] Towards molecular movies with X-ray photon correlation spectroscopy

F. Perakis and C. Gutt,

Phys. Chem. Chem. Phys, 22, 19443-19453 (2020).



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