Seminars Archive

Structural dynamics of water using XFELs

Abstract
In this talk I will give an overview or our recent activities in probing water dynamics using x-ray free electron lasers (XFELs). Specifically I will discuss 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, I will give a perspective of probing protein dynamics using these techniques and the discuss the open questions and challenges ahead [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, DOI: 10.1039/d0cp03551c (2020).