Brownian dynamics simulation of stiff dumbbells
نویسنده
چکیده
The effects of stiffness on the diffusion-limited dynamics of dumbbells in solution is studied numerically. The Langevin equation is used with two different models, the so-called Fraenkel and FENE dumbbells. It is found that the dynamics of rotation and stretching are dictated by the two following trends: (i) the density-density correlation function for these modes decays more slowly for larger values of the equilibrium distance between the two beads L (with the spring force constant K fixed), and (ii) it decays more quickly for increasing stiffness (with L fixed) making the bond stretching relaxation time 1" 2 smaller. For sufficiently stiff chains the value of 1" 2 becomes less than the delay time of the experimental correlator, resulting in a difference between the true and measurable first cumulants.
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