  The rate of escape of an ideal bead-spring polymer in a symmetric double-well
potential is calculated using transition state theory (TST) and the results
compared with direct dynamical simulations. The minimum energy path of the
transitions becomes flat and the dynamics diffusive for long polymers making
the Kramers-Langer estimate poor. However, TST with dynamical corrections based
on short time trajectories started at the transition state gives rate constant
estimates that agree within a factor of two with the molecular dynamics
simulations over a wide range of bead coupling constants and polymer lengths.
The computational effort required by the TST approach does not depend on the
escape rate and is much smaller than that required by molecular dynamics
simulations.
