J. Phys. IV France 10 (2000) Pr7-83-Pr7-86
Inelastic neutron scattering experiments on the fast dynamics of a glass forming liquid in mesoscopic confinementsR. Zorn1, D. Richter1, L. Hartmann2, F. Kremer2 and B. Frick3
1 Forschungszentrum Jülich, IFF, 52425 Jülich, Germany
2 Universität Leipzig, Institut für Experimentalphysik, Linnestr. 5, 04103 Leipzig, Germany
3 Institut Laue-Langevin, BP. 156, 38042 Grenoble cedex, France
In this article we report inelastic neutron scattering experiments on the dynamics of a confined glass forming liquid. The study was performed by the time-of-flight technique allowing access to an energy range 0.1-40 meV corresponding to the fast microscopic dynamics (0.1-20 ps). The most prominent effect was found for the "boson peak" close to 1 meV in the vibrational spectrum. A strong reduction of the modes at lowest frequencies could be observed. This result can be qualitatively explained by a cut-off of long wavelength soundlike modes but yet defies a quantitative description. In contrast to this the "fast process"—a short-time phenomenon of glass forming liquids at t < 1.5 ps—seems not to depend very strongly on the confinement. This result is in agreement with ideas of the local character of this process.
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