Anomalous temperature dependence of the experimental x-ray structure factor of supercooled water
| Autor: | Serhane Zerdane, Fivos Perakis, Katrin Amann-Winkel, Thomas J. Lane, Kyung Hwan Kim, Jayanath Koliyadu, Alexander Roland Oggenfuss, Philip J. M. Johnson, Harshad N Pathak, N. Esmaeildoost, Lemke Henrik, Roman Mankowsky, Alexander Späh, Cheolhee Yang, Marjorie Ladd-Parada, Jonas A. Sellberg, Anders Nilsson, Yunpei Deng, Paul Beaud |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Diffraction
Materials science 010304 chemical physics Scattering Atom and Molecular Physics and Optics Momentum transfer General Physics and Astronomy 01 natural sciences Molecular physics symbols.namesake Amplitude Fourier transform Teknik och teknologier 0103 physical sciences Amorphous ice Naturvetenskap symbols Engineering and Technology Atom- och molekylfysik och optik Physical and Theoretical Chemistry 010306 general physics Supercooling Structure factor Natural Sciences |
| Popis: | The structural changes of water upon deep supercooling were studied through wide-angle x-ray scattering at SwissFEL. The experimental setup had a momentum transfer range of 4.5 Å-1, which covered the principal doublet of the x-ray structure factor of water. The oxygen-oxygen structure factor was obtained for temperatures down to 228.5 ± 0.6 K. Similar to previous studies, the second diffraction peak increased strongly in amplitude as the structural change accelerated toward a local tetrahedral structure upon deep supercooling. We also observed an anomalous trend for the second peak position of the oxygen-oxygen structure factor (q2). We found that q2 exhibits an unprecedented positive partial derivative with respect to temperature for temperatures below 236 K. Based on Fourier inversion of our experimental data combined with reference data, we propose that the anomalous q2 shift originates from that a repeat spacing in the tetrahedral network, associated with all peaks in the oxygen-oxygen pair-correlation function, gives rise to a less dense local ordering that resembles that of low-density amorphous ice. The findings are consistent with that liquid water consists of a pentamer-based hydrogen-bonded network with low density upon deep supercooling. QC 20220125 |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|