Freely-jointed chains radial distribution function

Fig. 3. Site-averaged intermolecular radial distribution function g(r) for N = 200. The pants are the MD simulation of Kremer and Crest [27] (some points omitted for clarity). The solid line is the predicted result from the PRISM theory [27] using Ae simulated intramolecular d>(k)L The dashed line is the corresponding PRISM prediction using 6(k) from a freely jointed drain modd (with overlaps explicitly removed [14]). Rg is approximately 7.7 for the simulated chains...

Fig. 8. Radial distribution function W(r) of the chain displacement vectors for chain molecules consisting of lO freely jointed segments, each of length I = 0.25 nm W(r) is expressed in nm and r in nm (3). Courtesy of Cornell University Press.

Fig. 2. Intramolecular radial distribution functions from SC/PRISM (lines) and MD simulations (symbols) for melts of freely jointed (kbend = Ojpolymers with 20 and 100 monomers per chain for density = 0.85 and T = e/kg...

The intramolecular radial distribution functions from SC/PRISM for melts of N=20 and N=100 freely jointed (kbend = 0) chains (FJC) are shown in Fig. 2. Unlike analytical expressions for the intramolecular structure, the self-consistent approach captures all of the details of the intrachain structure and can be used for molecules of arbitrary complexity. The remaining differences are due to the approximate form of the solvation potential used in the self-consistent calculation. 

Figure 3 shows the intermolecular radial distribution functions obtained from SC/PRISM theory and MD simulations for freely jointed, bead-spring chain liquids in which the bond distance is comparable to the site diameter. As the chain length is increased, there is less structure for the first solvation shell due to increased screening... 

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