Models with Constraints

Mechanical models of polymers involving constraints have a long tradition in polymer kinetic theory (see Chap. 11 of [1]). The Kirkwood-Riseman chain proposed in 1948 consists of N beads and N — 1 rigid rods of length L with a fixed angle θ between successive links; links can rotate freely, that is, no rotatory potentials are included. This model is also called the freely rotating bead-rod chain. The Kramers chain proposed in 1944 is a freely jointed bead-rod chain with N beads and N — 1 rigid rods of length L.