A phase space analysis of the collinear I+HI reaction

Abstract

The collinear I+HI reaction is studied using an approach based on the concepts of nonlinear dynamics. Three closed regions in phase space are constructed by connecting the dynamical manifolds emanating from physically important periodic orbits. It is shown that many features of the reaction dynamics can be understood with reference to these regions. The oscillating reaction probability in this system is shown to stem from the geometrical pattern of overlap of heteroclinic oscillations of an interaction region. The process of complex formation is quantitatively described in terms of passage into a well defined complex region of phase space. The phase space representation predicts that the complex formation probability oscillates with energy and suggests that the complex lifetime might oscillate as well. We have carried out simulations which confirm both of these effects. The vibrational adiabatic approximation for the reaction is assessed relative to the exact classical dynamics.