Diffusion of a ring polymer in good solution via the Brownian dynamics with no bond crossing

Diffusion constants D R and D L of ring and linear polymers of the same molecular weight in a good solvent, respectively, have been evaluated through the Brownian dynamics with hydrodynamic interaction in which no bond crossing is possible. The ratio C = D R / D L , which should be universal in the context of the renormalization group, has been estimated as C = 1.14 ± 0.01 for the large- N limit. It should be consistent with that of synthetic polymers, while it is smaller than that of DNAs such as C ≈ 1.3. We also perform the same simulation through Brownian dynamics with hydrodynamic interaction where bond crossings are possible, and obtain almost the same estimate for the ratio C .