NONLINEAR RESONANCE AND DYNAMICAL CHAOS IN A DIATOMIC MOLECULE DRIVENBY A RESONANT IR FIELD

We consider the transition from regular motion to dynamical chaos in a classical model of a diatomic molecule which is driven by a circularl y polarized resonant ir field. Under the conditions of a nearly two-di mensional case, the Hamiltonian reduces to that for the nonintegrable motion of a charged particle in an electromagnetic wave [A. J. Lichten berg and M. A. Lieberman, Regular and Stochastic Motion (Springer-Verl ag, City, 1983)]. In the general case, the transition to chaos is conn ected with the overlapping of vibrational-rotational nonlinear resonan ces and appears even at rather low radiation held intensity, S greater than or similar to 1 GW/cm(2). We also discuss the possibility of exp erimentally observing this transition.