Phase Space Structures in 3 and 4 Degrees of Freedom: Application to Chemical Reactions

Abstract

We investigate the dynamics of the reaction Ar + Ar₂ → Ar₂ + Ar by propagating classical trajectories sampled from a distribution of initial conditions. The trajectories can be classed as direct or indirect depending on whether they are ‘trapped’ within the interaction zone for any significant period of time. ‘Direct’ trajectories can be understood in terms of simple billiard-ball mechanisms. It is found that a subset of periodic orbits corresponding to internal rotation within the Ar₃ complex is responsible for ‘indirect’ trajectories. The location and stability of these periodic orbits is investigated as a function of the total energy and total angular momentum of the Ar₃ complex and a bifurcation sequence that gives rise to an infinite family of periodic orbits is observed.