Thesis defense of Joachim Beerwerth

Dynamic processes in molecular and ionic crystals are investigated using central line NMR on the strongly quadrupolar perturebed nuclei 11B and 17O. For this purpose, 11B relaxation times are measured in orthocarborane and interpreted in terms of molecular dynamics. In sodium nitrate, the three side jump of the planar nitrate group is studied by 17O NMR. The dynamics of the ion are investigated by NMR spectra, stimulated echoes and relaxation times. Combining the results from simulations with measured spectra, jump rates are determined. A 17O high temperature spectrum of sodium nitrate is described using averaged tensors. The reorientational dynamics in sodium nitrate has an activation energy of EA = 0.38 eV. As an example for a tetrahedral jump, potassium permanganate is studied using 17O NMR. Here, with the aid of stimulated echoes, an activation energy of EA = 0.35 eV is determined for the jumps of oxygen atoms. The relaxation times are also measured for potassium permanganate and interpreted with respect to the reorientational dynamics.

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