The dynamic response function χT(Q,t) of confined supercooled water and its relation to the dynamic crossover phenomenon

Sow Hsin Chen, Yang Zhang, Marco Lagi, Xiangqiang Chu, Li Liu, Antonio Faraone, Emiliano Fratini, Piero Baglioni

Research output: Contribution to journalShort surveypeer-review

Abstract

We have made a series of Quasi-Elastic Neutron Scattering (QENS) studies of supercooled water confined in 3-D and 1-D geometries, specifically, interstitial water in aged cement paste (3-D) and water confined in MCM-41-S and Double Wall Nano Tube DWNT (l-D). In addition, we also include the cases of hydration water on protein surface and other biopolymer surfaces (pseudo 2-D). By analyzing the QENS spectra using Relaxing Cage Model (RCM), we are able to extract accurately the self-intermediate scattering function of hydrogen atoms FH(Q,t), at low-Q as a function of temperature T, showing an α-relaxation process at long time. We can then construct the Dynamic Response Function χT(Q,t) = -dFH(Q,t)/dT. χT(Q,t) as a function of t at constant Q shows a single peak at the characteristic α-relaxation time (τ), the amplitude of which grows as we approach the dynamic crossover temperature TL observed before in each of these geometries. However, the peak height of χT(Q,t) decreases after passing the crossover temperature TL. We make an argument to relate the occurrence of the extremum of the peak height in χT to the existence of the dynamic crossover temperature in each of these cases.

Original languageEnglish (US)
Pages (from-to)109-131
Number of pages23
JournalZeitschrift fur Physikalische Chemie
Volume224
Issue number1-2
DOIs
StatePublished - 2010

Keywords

  • Confined supercooled water
  • Dynamic crossover phenomenon
  • Dynamic response function

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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