Saddle-node bifurcations in the LiNC/LiCN molecular system: Classical aspects and quantum manifestations

A classical-quantum correspondence study elf a saddle-node bifurcation in a realistic molecular system is presented, The relevant classical structures (periodic orbits and manifolds) and its origin are examined in detail. The most important conclusion of this study is that, below the bifurcation point, there exists an Infinite sequence of precursor orbits, which mimic for a significant period of time the (future) saddle-node orbits. These structures have a profound influence in the quantum mechanics of the molecule and several vibrational wave functions of the system present a strong localization along the saddle-node periodic orbits. A striking result is that this scarring effect also takes place well below the bifurcation energy, which constitutes a manifestation of the set-called ''ghost'' orbits In configuration and phase space. This localization effect has been further investigated using wave packet dynamics. (C) 1996 American Institute of Physics.