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

Abstract

We study the effect of overlapping resonances on the angular distributions of the reaction F+H2(v=0,j=0)-->HF(v=2,j=0)+H in the collision energy range from 5 to 65 meV, i.e., under the reaction barrier. Reactive scattering calculations were performed using the hyperquantization algorithm on the potential energy surface of Stark and Werner [J. Chem. Phys. 104, 6515 (1996)]. The positions of the Regge and complex energy poles are obtained by Pade 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.

Computer Software for Understanding Resonances and Resonance-Related Phenomena in Chemical Reactions

“…After all resonances contributions have been removed, we are left with the 'direct' part of the cross section, often similar to the integral in Eq. (9). An illustration is given in Fig.…”

“…Future work Angular distributions, also known as differential cross sections (DCS), contain other detailed information of the reaction mechanism, and are more difficult to interpret. Although there has been much work on the analysis of DCSs in terms of trajectories and resonance poles 12,13,16,14,18,19,27,26, no computer codes have yet been produced for public use. This Section is, therefore, more a statement of intent than a description of existing software.…”

“…(9) is exact, this last term can be evaluated as the difference between the term in the l.h.s and the first two terms in the r.h.s of Eq. (9).. This is a formula which can be evaluated after performing Padé reconstruction described in the previous Section.…”

Numerical Regge pole analysis of resonance structures in elastic, inelastic and reactive state-to-state integral cross sections

“…[9], and analysed in Refs. [34]- [35], [40]. In the specified energy range there are two resonance Regge trajectories, both contributing to the Regge oscillations seen in the state-to-state integral cross section.…”

“…Resonance Regge poles are closely related to the resonance complex energy poles [34], [14], [40], but are more convenient for the analysis of the quantities given by partial wave sums at a fixed energy, like the ICS in Eqs.…”