Influence of reptations on conformations of the homopolymer in Monte Carlo simulation

We study the role of topological restrictions for the conformational structure of a nonphantom homopolymer chain in a lattice Monte Carlo model. In the athermal regime we find that the standard Metropolis algorithm violates the detailed balance condition if both local monomer and global reptational moves are included. However, if about 1 reptation is performed per N local moves the balance is recovered and we obtain the Flory exponent value close to nu=0.588, where N is the degree of polymerisation. We also find that the structure of the collapsed globule is different at equilibrium from that after the late stage of folding kinetics. Namely, due to reptations the end, and even more so, the penultimate monomer groups tend to be buried inside the globule core with other monomers thus being more exposed to the surface.