Cooperative dynamics in unentangled polymer fluids.

We present a generalized Langevin equation for the dynamics of interacting semiflexible polymer chains undergoing slow cooperative dynamics. The calculated Gaussian intermolecular center-of-mass and monomer potentials are in quantitative agreement with computer-simulation data. The experimentally observed short-time subdiffusive regime of the polymer mean-square displacement emerges from the competition between intra- and intermolecular mean-force potentials.