2025-07-03 パシフィック・ノースウェスト国立研究所（PNNL）
＜関連情報＞
- https://www.pnnl.gov/publications/existence-deeply-supercooled-liquid-water
- https://pubs.acs.org/doi/full/10.1021/acs.jpclett.5c00245
ガラス転移温度付近における過冷却液体水の拡散率 Supercooled Liquid Water Diffusivity at Temperatures near the Glass Transition Temperature
R. Scott Smith,Wyatt A. Thornley,Greg A. Kimmel,and Bruce D. Kay
The Journal of Physical Chemistry Letters Published: March 20, 2025
DOI:https://doi.org/10.1021/acs.jpclett.5c00245
Abstract
Isotopically layered amorphous solid water films were used to measure the diffusivity of deeply supercooled liquid water near the glass transition. The films, composed of separate H218O and H216O layers, were grown by vapor deposition at low temperature and then heated to observe the intermixing of the isotopic layers. Very slow heating rates (as low as 10–4 K/s) were used to decouple the diffusion and crystallization processes to ensure that the observed intermixing occurred at temperatures that were well-separated from the onset of crystallization. Numerical simulations of the desorption spectra were used to extract the translational diffusivities. The diffusivities obtained in this paper are consistent with translational liquid-like motion at temperatures near and above the proposed Tg of 136 K. These findings support the idea that the melt of amorphous water, above its glass transition temperature is thermodynamically continuous with normal supercooled liquid.
