Morse bifurcations of transition states in bimolecular reactions

TL;DR

This paper explores Morse bifurcations in transition states of bimolecular reactions, revealing their qualitative changes and persistence over a range of energies, with detailed examples and discussion on system reduction complexities.

Contribution

It introduces the concept of Morse bifurcations in transition states for bimolecular reactions and provides concrete examples involving atom-diatom and general molecule capture.

Findings

Transition states undergo Morse bifurcations affecting reaction pathways.

Transition states exist over a broad energy range, not just near the critical energy.

Reduction of n-body systems presents challenges in global geometry analysis.

Abstract

The transition states and dividing surfaces used to find rate constants for bimolecular reactions are shown to undergo qualitative changes, known as Morse bifurcations, and to exist for a large range of energies, not just immediately above the critical energy for first connection between reactants and products. Specifically, we consider capture between two molecules and the associated transition states for the case of non-zero angular momentum and general attitudes. The capture between an atom and a diatom, and then a general molecule are presented, providing concrete examples of Morse bifurcations of transition states and dividing surfaces. The reduction of the $n$-body systems representing the reactions is discussed and reviewed with comments on the difficulties associated with choosing appropriate charts and the global geometry of the reduced spaces.