Molecular dynamics with coupling to an external bath
The renormalized elastic theory for isolated flexible polymers developed by P. G. deGennes (1976) is extended to include strong elongation with Z/RF >>1 (Z = av. end-to-end length under uniform tension, RF is the excluded vol. Flory radius of a free coil). In this regime the elastic restoring force is nonlinear in distortion and varies with Z1.5 in 3 dimensions. The consequences of this behavior are discussed in relation to coil-stretch transition in strong shear flow and to elastic neutron scattering.