A concerted rotation algorithm for atomistic Monte Carlo simulation of polymer melts and glasses

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Abstract
We develop and test a new elementary Monte Carlo move for use in the efficient simulation of polymer systems. The move consists of a concerted rotation around up to seven adjacent skeletal bonds that leaves the rest of the chain unaffected. No assumption is made concerning the backbone geometry other than that bond lengths and bond angles are held constant during the elementary move. Special sampling techniques are needed because the new move involves a correlated change in seven degrees of freedom along the chain backbone. We use the new move in conjunction with reptation in an isothermal-isobaric Monte Carlo simulation of a bulk tetracosane melt system and find that it improves computational efficiency relative to a purely reptation-based Monte Carlo scheme. Comparisons are also made between a concerted rotation-based Monte Carlo simulation and a molecular dynamics simulation of an oligomer of atactic polypropylene.