Monte Carlo study of freely jointed ring polymers. II. The writhing number

Recently, the study of writhing in ring polymers has attracted considerable attention in relation to the study of torsional stiffness of DNA molecules in solution (see Refs. 6 and 10). In the first paper of this series we proposed an efficient dimerization method of generating ring polymers of the freely jointed model. In this paper we calculate the writhing numbers and their statistical distribution functions for the rings generated by this method. The results are compared with those obtained by LeBret (Ref. 10) and Vologodskii et al. (Ref. 6), in which the ring polymers were generated by a method completely different from out dimerization method. It seems that the writhing numbers may not be very sensitive to the ring generation procedure, but rather sensitive to the polymer model and its parameters.