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DY: Dynamik und Statistische Physik

DY 53: Gl
äser III

DY 53.8: Vortrag

Freitag, 30. März 2001, 13:15–13:30, S 7

Dynamic light- and X-ray scattering in molecular fluids and glasses. — •Martin Letz and Arnulf Latz — Institut für Physik, Johannes-Gutenberg Universität Mainz

Depending on the scattering geometry light scattering measures a mixture of correlation functions which transform differently under rotations. The rotational symmetry however defines which hydrodynamic mode can be measured in the various scattering geometries. We therefore derive a set of equations which defines the contributions of correlation functions with different rotational symmetries to light scattering spectra of molecular liquids and glasses and relate them to a microscopic theory for the dynamics of these systems. Among other results we conclude that it is crucial to take the helicity index ”m” occurring in a spherical harmonics expansion serious [1]. This is necessary even for the small but finite wave-vector of a light-scattering experiment but even more for X-ray scattering experiments.

[1] A. Latz, M. Letz, cond-mat/0007029, to appear in EJP.B