  The study of the noise induced effects on the dynamics of a chain molecule
crossing a potential barrier, in the presence of a metastable state, is
presented. A two-dimensional stochastic version of the Rouse model for a
flexible polymer has been adopted to mimic the molecular dynamics and to take
into account the interactions between adjacent monomers. We obtain a
nonmonotonic behavior of the mean first passage time and its standard
deviation, of the polymer centre of inertia, with the noise intensity. These
findings reveal a noise induced effect on the mean crossing time. The role of
the polymer length is also investigated.
