Anisotropic X-Ray Scattering of Transiently Oriented Water
Kyung Hwan Kim, Alexander Späh, Harshad Pathak, Cheolhee Yang, Stefano Bonetti, Katrin Amann‐Winkel, Daniel Mariedahl, Daniel Schlesinger, Jonas A. Sellberg, Derek Mendez, Gijs van der Schot, Harold Y. Hwang, Jesse N. Clark, Shigeki Owada, Tadashi Togashi, Yoshihisa Harada, Hirohito Ogasawara, Tetsuo Katayama, Anders Nilsson, Fivos Perakis
Abstract
We study the structural dynamics of liquid water by time-resolved anisotropic x-ray scattering under the optical Kerr effect condition. In this way, we can separate the anisotropic scattering decay of 160 fs from the delayed temperature increase of ∼0.1 K occurring at 1 ps and quantify transient changes in the O-O pair distribution function. Polarizable molecular dynamics simulations reproduce well the experiment, indicating transient alignment of molecules along the electric field, which shortens the nearest-neighbor distances. In addition, analysis of the simulated water local structure provides evidence that two hypothesized fluctuating water configurations exhibit different polarizability.