Discretizing elastic chains for coarse-grained polymer models

Studying the statistical and dynamic behavior of semiflexible polymers under complex conditions generally requires discretizing the polymer into a sequence of beads for purposes of simulation. We present a novel approach for generating coarse-grained, discretized polymer models designed to reproduce the polymer statistics at intermediate to long lengths. Our versatile model allows for an arbitrary discretization length and is accurate over a larger range of length scales than the traditional bead-rod and bead-spring models. In its generality, the discrete, stretchable, shearable wormlike chain (dssWLC) model incorporates the anisotropic elasticity inherent in a semielastic chain on intermediate length scales. We demonstrate quantitatively the statistical accuracy of this model at different discretizations, thereby allowing for efficient selection of the number of segments to be simulated. The approach presented in this work provides a systematic procedure for generating coarse-grained discrete models to probe physical properties of a semielastic polymer at arbitrary length scales.