Dynamics of complex molecules and multidimensional nuclear magnetic resonance

The relation between multidimensional Nuclear Magnetic Resonance (NMR) techniques and the dynamical behaviour of complex molecules is considered in this work. Two important NMR-interactions, the chemical shift and anisotropic contributions in the case of restricted motions of molecules, are introduced and discussed in two well-established models for polymer dynamics. Complex molecules exhibit non-trivial time-dependent interactions between relaxing or diffusing units. Dense polymer melts are considered, where the crossing of chains is prohibited and excluded-volume interactions affect the dynamics. Multidimensional NMR-techniques allow for the characterization and correlation of molecular conformations at successive points in time. The notion of "dimensionality" refers to the number of correlated points in time; here the two-dimensional case is considered. In the first part of the thesis, analytical investigations for a simplified model of polymer dynamics are presented. A two-point correlation-function or, equivalently, a joint probability - with which the outcome of a 2D NMR experiment can be compared - is calculated for the Rubinstein-model. The results are displayed in histograms, which have been designed according to 2D NMR spectra. In the second part of the thesis, computer-simulations of a three-dimensional coarse grained model for polymer dynamics were carried out. Monte-Carlo simulations of the bondfluctuation-model for chains of different length were performed with particular emphasis on neighbourhood-conditions of monomers and bond-orientations. The correlation-functions obtained were visualized in two-dimensional spectra. From both models, information on local dynamical properties of polymer chain segments was extracted and related to the effects on simulated 2D NMR spectra