Monte Carlo studies of lattice‐model polymer chains. III. Relaxation of Rouse coordinates

The relaxation of the seven lowest Rouse coordinates for simple lattice models of polymer chains of up to 64 beads, with and without excluded volume, is studied by simulation on a digital computer. The similarity between the relaxation of the lattice‐model chains without excluded volume and that of a statistical‐bead model, noted in previous studies of end‐to‐end length, is confirmed and examined in greater detail. The effect of excluded volume in slowing down the relaxation of the Rouse coordinates is examined, and a simple picture is suggested which accounts qualitatively for the results obtained. The nonnormal coordinate nature of the Rouse coordinates for chains with excluded volume is demonstrated by their nonexponential autocorrelation functions. However, the results suggest that for each chain length, there is a unique longest internal relaxation time, corresponding to an internal coordinate closely resembling the lowest Rouse coordinate.