Dynamical properties of confined supercooled water: An NMR study

Francesco Mallamace, Matteo Broccio, Carmelo Corsaro, Antonio Faraone, Li Liu, Chung Yuan Mou, Sow Hsin Chen

研究成果: 雜誌貢獻文章同行評審

53 引文 斯高帕斯(Scopus)

摘要

We report a set of dynamical data of confined water measured in a very deeply supercooled regime (290-190K). Water is contained in silica matrices (MCM-41-S) which consist of 1D cylindrical pores with diameters d ≤ 14,18 and 24. When confined in these tubular pores, water does not crystallize, and can be supercooled well below 200K. We use the NMR technique to obtain the characteristic proton relaxation time-constants (the spin-lattice relaxation time-constant T1 and the spin-spin relaxation time-constant T2) and a direct measurement of the self-diffusion coefficient in the whole temperature range. We give evidence of the existence of a fragile-to-strong dynamic crossover (FSC) at TL ≤ 225K from the temperature dependence of the self-diffusion coefficient. A combination of the NMR self-diffusion coefficient with the average translational relaxation time, as measured by quasi-elastic neutron scattering, shows a well defined decoupling of transport coefficients, i.e. the breakdown of the Stokes-Einstein relation, on approaching the crossover temperature TL.

原文英語
文章編號S04
頁(從 - 到)S2285-S2297
期刊Journal of Physics Condensed Matter
18
發行號36
DOIs
出版狀態已發佈 - 9月 13 2006
對外發佈

ASJC Scopus subject areas

  • 材料科學(全部)
  • 凝聚態物理學

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