| Contents |
| In a chemical reaction, reactant and product regions are kept apart by a saddle point (a barrier).
Thence, every reactive trajectory starts in the reactant region, crosses the barrier, and it
enters in the product region. In this contest, Transition State Theory (TST)
plays a fundamental role. The main assumption of this theory relies on the existence
in phase space of a dividing surface located at the neighborhood of the barrier, the so-called
Transition State (TS). A proper TS separates reactants from products,
it is only crossed by reactive trajectories, and it is a non-recrossing surface in the sense that
reactive trajectories must cross it only once. As long as the energy
of the reaction remains close enough to the saddle point energy, the
saddle point region present the so-called bottleneck structure and the TS preserves its
non-recrossing property. However, as the energy increases, the
bottleneck structure of the saddle region is lost and the non-recrossing property of the TS
is lost due to the appearance of additional dynamical
barriers in the saddle region. In this contest, the main subject of this talk is the study of the mechanisms
for the appearance of those additional dynamical
barriers. |
|