Pivot-coupled grand canonical monte carlo method for ring simulations

摘要

A new method is presented fro the simulation of an ensemble of polymer rings of variable size at fixed monomer chemicl potential.Called pivot-coupled grand canonical Monte Carlo (PC-GCMC),it is based on the directed addition or removal of a monomer to or from a ring,coupled to the pivot of a section of the ring to maintain the ring's continuity.Application of PC-GCMC to simgle,isolated rings yields the free energy of the ring polymer as a functionof number of monomers,information useful in determining equilibrium constants fro polymer cyclization.Ring closure probabilities ("J-factors")for flexible and semiflexible polymers.both ideal and self-avioding,in two and three dimensions are obtained in close agreement with available results from theory and other simulation methods.New results are obtained for two-dimensional semiflexible polygons.Potential applications of the method to simulations of ring-forming equilibrium polymers.disklike micelles,and self-assembling polymer loops are discussed.