The behavior of linear macromolecules with some flexibility is considered. A lsquo;lsquo;trumbellrsquo;rsquo; model is used which consists of three beads connected by two rigid rods and a hinge with a restoring force proportional to the angle of bending at the middle bead. This model, which has four curvilinear nonorthogonal configurational coordinates, seems to be the most complex that can be solved completely at present. The relaxation spectrum lgr;iis found for different values of the relative bending force constantZ=egr;/kTby numerical integration of Kirkwoodrsquo;s diffusion equation using Hassagerrsquo;s collocation method. The viscoelastic behavior is calculated by extending Hassagerrsquo;s procedure. The results show two main contributions: (i) a slow relaxation lgr;1which is nearly pure rotation and which tends to the rigidhyphen;rod limit asZincreases, (ii) a fast mixed bendhyphen;rotation relaxation lgr;2proportional toZ. A purehyphen;bending mode of relaxation also exists, but it does not contribute to the viscoelastic behavior of the model.
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