Experimentally constrained molecular relaxation

We do this by combining data from high-energy XRD [18] and XPS measurements on a- and c-GST [19] with DF simulations of a 460-atom sample over hundreds of picoseconds. This strategy is related to the experimentally constrained molecular relaxation (ECMR) of Biswas et al. [21, 22]. 

Entanglements of flexible polymer chains contribute to non-linear viscoelastic response. Motions hindered by entanglements are a contributor to dielectric and diffusion properties since they constrain chain dynamics. Macromolecular dynamics are theoretically described by the reptation model. Reptation includes fluctuations in chain contour length, entanglement release, tube dilation, and retraction of side chains as the molecules translate using segmental motions, through a theoretical tube. The reptation model shows favourable comparison with experimental data from viscoelastic and dielectric measurements. The model reveals much about chain dynamics, relaxation times and molecular structures of individual macromolecules. 

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