Scattering Matrix in Reactive collision theory: from resonances to rate constants

A newly developed model that serves to evaluate the energy position and the lifetime of metastable states in the case of overlapping resonances is presented. As an application of this theory, the interesting case of two interacting resonances which occur in the F + H-2 reaction has been analyzed in the energy interval where they overlap. We show that the changes induced by molecular rotations on both the positions and the lifetimes produce quantum oscillating structures in the integral cross section. This rich resonance pattern is crucial in enhancing the reaction rate and extremely sensitive to the details of the interaction.