Quasielastic and inelastic neutron scattering investigation of fragile-to-strong crossover in deeply supercooled water confined in nanoporous silica matrices

Li Liu, Sow Hsin Chen, Antonio Faraone, Chun Wan Yen, Chung Yuan Mou, Alexander I. Kolesnikov, Eugene Mamontov, Juscelino Leao

Research output: Contribution to journalArticlepeer-review

89 Citations (Scopus)

Abstract

We investigated, using quasi-elastic and inelastic neutron scattering, the slow single-particle dynamics of water confined in laboratory synthesized nanoporous silica matrices, MCM-41-S, with pore diameters ranging from 10 to 18. Inside the pores of these matrices, the freezing process of water is strongly inhibited down to 160K. We analysed the quasi-elastic part of the neutron scattering spectra with a relaxing-cage model and determined the temperature and pressure dependence of the Q-dependent translational relaxation time and its stretch exponent β for the time dependence of the self-intermediate scattering function. The calculated Q-independent average translational relaxation time shows a fragile-to-strong (FS) dynamic crossover for pressures lower than 1600bar. Above this pressure, it is no longer possible to discern the characteristic feature of the FS crossover. Identification of this end point with the predicted second low-temperature critical point of water is discussed. A subsequent inelastic neutron scattering investigation of the librational band of water indicates that this FS dynamic crossover is associated with a structural change of the hydrogen-bond cage surrounding a typical water molecule from a denser liquid-like configuration to a less-dense ice-like open structure.

Original languageEnglish
Article numberS03
Pages (from-to)S2261-S2284
JournalJournal of Physics Condensed Matter
Volume18
Issue number36
DOIs
Publication statusPublished - Sep 13 2006
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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