Directed bridging methods for fast atomistic Monte Carlo simulations of bulk polymers

A new class of Monte Carlo algorithms for atomistic simulation of genuine h igh polymer systems is proposed. Derivations of two of these algorithms, du bbed "directed internal bridging" (DIB) and "directed end bridging" (DEB), are presented. Their performance is analyzed in detail, using linear united -atom polyethylene of mean chain length C-1000 as an archetypal entangled p olymer melt. It is shown in particular that the DEB algorithm is substantia lly faster than previous alternatives in equilibrating such melts on all le ngth scales. Used in a suitable protocol of mixed Monte Carlo moves, it thu s provides the most powerful means available to date for quantitative molec ular simulation of such materials, and makes atomic level characterization of realistic high polymer melts a feasible proposition.