A route to chaos in classical atom–diatom collisions

We study classical atom–diatom collisions in the `T-shapedʹ configuration. Considering collisions of helium atoms with a bound I2 molecule at high energies, the scattering process becomes increasingly complicated as the projectile energy is lowered. The complexity manifests itself in phase space structures which change in a well defined way forming a `route to chaosʹ. An analysis of this route provides a deeper understanding of the appearance of chaos in three-body collisional systems. Our perspective is complementary to approaches dealing directly with the fractal properties of observables in the chaotic regime.