  We present a modified version of the nudged elastic band (NEB) algorithm to
find minimum energy paths con-necting two known configurations. We show that
replacing the harmonic band-energy term with a discretized version of the
Onsager-Machlup action leads to a NEB algorithm with adaptive spring lengths
that automatically increase the resolution of the minimum energy path around
the saddle point of the potential energy surface. The method has the same
computational cost per optimization step of the standard NEB algorithm and does
not introduce additional parameters. We present applications to the
isomerization of alanine dipeptide, the elimination of hydrogen from ethane and
the healing of a 5-77-5 defect in graphene.
