Interacting resonances in the F + H2 reaction revisited: complex terms, Riemann surfaces and angular distributions.

We study the effect of overlapping resonances on the angular distribution of the title reaction in the collision energy range 5-65 meV, i.e., under the reaction barrier. The positions of the Regge and complex energy poles are obtained by Padé reconstruction of the scattering matrix element. The Sturmian theory is invoked to relate the Regge and complex energy terms. For two interacting resonances, a two-sheet Riemann surface is contracted and inverted. The semiclassical complex angular momentum analysis is used to decompose the scattering amplitude into the direct and resonance contributions.