Harmonic modes of a disordered zig-zag chain

We describe the results of a simulation of a model of a random chain embedded as a self-avoiding walk on a diamond lattice. The dynamic model is the same as Kirkwood's. The equation of motion method we use permits such functions as S(k, ω), the dynamic structure factor, to be calculated as easily as the density of states. We present results on the density of states and S(k, ω) for chains of 1000 monomers. The results illustrate a mechanism of harmonic self-stabilization of a chain, which we also discuss in physical terms. We believe that simulations of this type can be useful to experimentalists in relating spectral features to morphology.