Gusev-Suter method

Here, r1 (t)is the position vector of penetrant i and < > is the average over all possible time origins t = 0 and all simulated trajectories of a penetrant of a given kind. Again, as with the solubilities the Gusev-Suter method can only handle small penetrants in this way, because the respective polymer matrix cannot conformationally adjust to larger penetrants. Table 1.3 contains a comparison between experimental and... 

Application to heterogeneous polymer solids, and elastic composites, is presented in the Section 7 (Gusev, Suter), which is followed by a summary and the outlook for the various methods reviewed here. It will be apparent to the reader that this review thus assembles several building blocks for the difficult task to bridge the gaps from the atomistic to the macroscopic scales in space and times for the simulation of polymeric materials. Integrating these building blocks into one coherent framework still is not fully solved and a matter of current research. 

In the original Gusev Suter TST method a frozen polymer method has been used. All polymer chains are considered fixed in place, and TST-based rate constants are calculated from the energy barriers found for a penetrant to pass from one local potential energy minimum to another. This method is the most straightforward however, in polymers it yields rate constants that lead to diffusion coefficients much lower (by factors of 10 10 ) than experimental values, because neglecting chain fluctuation contributions is physically... 

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