Figure 2.

Considerations of potential energy hypersurfaces. Pictorial presentation of the formulation of a unified reactivity paradigm that dissects and combines, compares, and contrasts over-the-barrier thermal reactions and intrinsic and thermodynamic contributions to the overall reactivity. The intrinsic barrier height reflects the reorganization energy, whereas the intrinsic barrier width reflects the reorganization distance. As the barrier width is most significantly (though not exclusively) represented by QMT, we take the barrier width as the reorganization distance over which the wave functions of the reactant state extend into the classically forbidden region under the barrier.