  We present the capability of Lagrangian descriptors for revealing the high
dimensional phase space structures that are of interest in nonlinear
Hamiltonian systems with index-1 saddle. These phase space structures include
normally hyperbolic invariant manifolds and their stable and unstable
manifolds, and act as codimenision-1 barriers to phase space transport. The
method is applied to classical two and three degrees-of-freedom Hamiltonian
systems which have implications for myriad applications in physics and
chemistry.
