| Abstract
| - The analysis of residual dipolar couplings from an ensemble of conformations to extract moleculardynamics is intricate. The very mechanism that is necessary to perturb overall molecular tumbling to generatenonvanishing residual dipolar couplings gives rise to convoluted data. The measured values are essentiallyweighted averages over conformations. However, the weights are not simply the populations ofconformations. Consequently, the observed order parameter is not exactly the true measure of motion. Inthe case of paramagnetic alignment, the apparent order parameter is expected to depend on the numberof torsions that separate the locus of interest from the paramagnetic site. In the case of alignment due tosteric obstruction, the uneven selection of conformations by their differing Saupe order matrices leads toa bias in the residual dipolar couplings-probed molecular dynamics.
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