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RESEARCH PRODUCT
Localized Motion in Supercooled Glycerol as Measured by 2 H-NMR Spin-Lattice Relaxation and Incoherent Neutron Scattering
Winfried PetryF. FujaraW. SchnaussR. M. DiehlHans Sillescusubject
Materials scienceCondensed matter physicsPhononSpin–lattice relaxationGeneral Physics and AstronomyNeutron scatteringMolecular physicssymbols.namesakeDeuteriumsymbolsRelaxation (physics)van der Waals forceGlass transitionSupercoolingdescription
Selectively deuterated glycerol has been subjected to 2H-NMR spin-lattice relaxation and quasi-elastic neutron scattering experiments. The measurements yield relaxation rates and a non-Gaussian Q-dependence of the Debye-Waller factor which are different for the two hydrogen sites. The data analysis shows that below the onset of the glass transition α-process the hydrogens perform a local motion (≈ 10-12 s) in addition to what is expected from harmonic phonons. The resulting mean-square displacements are highly temperature dependent but are significantly smaller than those found in van der Waals glasses. Amplitudes and activation energies of the carbon-bonded and oxygen-bonded hydrogens are different. A possible mechanism is discussed.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1991-03-15 | Europhysics Letters (EPL) |