Persistence length of the Debye-Huckel model of weakly charged flexible polyelectrolyte chains

We present simulations of the basic analytic model of weakly charged polyelectrolytes: monovalently charged monomers with Debye-Huckel interaction coupled by harmonic springs. Quantities such as the chain radii, bond lengths, structure factors, persistence lengths, and scaling properties were examined. The persistence length L(p) shows a sublinear dependence on the screening length r(D)=1/kappa (L(p) similar to kappa(-y),y<1) in strong contrast to all known analytical approaches which propose either y=2 or y=1. The observed exponent y varies as a function of kappa and the bond length b.