Structural dynamics of water using XFELs
F. Perakis, Chemical Physics, 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).
https://www.nature.com/articles/s41467-018-04330-5
[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).
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.125.076002
[3] Towards molecular movies with X-ray photon correlation spectroscopy
F. Perakis and C. Gutt,
Phys. Chem. Chem. Phys, 22, 19443-19453 (2020).
https://doi.org/10.1039/D0CP03551C