Coherent structural relaxation of water from meso- to intermolecular scales measured using neutron spectroscopy with polarization analysis

• DOI: 10.1103/physrevresearch.2.022015
• Publication Date: 2020-04-17T15:32:12Z
• Authors: Arantxa Arbe; Gøran J. Nilsen; J. Ross Stewart; Fernando Alvarez; Victoria García S...; Juan Colmenero
• Keywords: Physics; QC1-999; 0103 physical sciences; 01 natural sciences

Peer reviewed<br/>Authors from the Materials Physics Center (San Sebastián) gratefully acknowledge the financial support of the Eusko Jaurlaritza, code IT-1175-19, and the Ministerio de Economía y Competitividad code PGC2018-094548-B-I00 (MCIU/AEI/FEDER, UE).<br/>By means of the recent implementation of neutron polarization analysis on a wide-angle time-of-flight spectrometer, we have been able to separately measure coherent and incoherent dynamic structure factors of heavy water with sub-meV resolution in a wide scattering vector (Q) range. The observed decorrelation of collective fluctuations at mesoscales hardly depends on Q. In the crossover towards intermolecular scales, the coherent dynamics is nicely described by the convolution of a Q-independent mode and diffusion, in addition to collective excitations.<br/>