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SYMR: Symposium Nuclear Magnetic Resonance: from Applications in Condensed-Matter Physics to New Frontiers
SYMR 8: Glasses and Glass Transition
SYMR 8.3: Vortrag
Mittwoch, 24. März 2010, 14:45–15:00, H48
The elusive nature of the Debye process in monohydroxy alcohols: A new approach with 2H-NMR techniques — •Sebastian Schildmann, Catalin Gainaru, and Roland Böhmer — Experimentelle Physik III, Fakultät für Physik, Technische Universität Dortmund
Viscous monohydroxy alcohols, also water, exhibit a so called Debye process in their dielectric spectra. This relaxational feature corresponds to degrees of freedom which are about 100 times slower than those giving rise to the structural rearrangements (α-process). In spite of numerous experimental investigations [1], the nature of these slow "superstructure" relaxation modes is not agreed upon, although it is clear that they are to be related with the presence of hydrogen bonds. The Debye process separates from the structural process if the network is interrupted chemically by diluting or topologically by confining the system in pores. Here butanol diluted with bromobutane was studied with several 2H-NMR techniques. Correlation times measured with stimulated-echo experiments are compared with data obtained from dielectric spectroscopy [2]. Spin-lattice relaxation times were measured for O-D deuterated samples to check how the hydrogen bonds affect the dynamics.
[1] M. Poeschl & H.G. Hertz, J. Phys. Chem. 98, 8195 (1994).
[2] T. El Goresy & R. Böhmer, J. Chem. Phys. 128, 154520 (2008).
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