ORIENTATIONAL RELAXATION-TIMES OF WORM-LIKE CHAINS

A semi-empirical formula for orientational relaxation times of worm-li ke chains in dilute solutions is proposed tau congruent to 27/8 x(3) . [1 - 3/4 x + 3/4 x exp (- 4/3x)](3) tau(rod) where tau(rod) = tau(0)N (3) is the relaxation time of a rigid rod composed of N segments, and x = 2a/L is the chain rigidity, i.e. the ratio of the double persisten ce length to the chain contour length, L. The formula, which can be us ed in the entire range of molecular rigidities and chain lengths, has been tested against segment relaxation times for semi-rigid chains cal culated from the optimized Rouse-Zimm model.