Journal of Chemical Physics, Vol.116, No.3, 1022-1029, 2002
Rabi oscillations in the dissociative continuum: Rotation and alignment effects
We have simulated a set of experiments in which Rabi oscillations are induced in bound-free and free-free transitions of a diatomic molecule. Dissociative vibrational states belonging to different electronic terms are involved. We show analytically and confirm computationally that a simple relationship exists between the one-dimensional dynamics of a molecule with fixed orientation with respect to the polarization of the radiation field and the three-dimensional dynamics of a rotating system. It is demonstrated that sufficiently short laser pulses can induce oscillations in the probabilities of two coupled electronic states, and in the yields of the respective dissociation products, as functions of the radiation intensity. As a result of molecular rotation the oscillations are damped but not washed out. The initial thermal distribution on several rotational levels has a negligible effect on the photodissociation yields and other experimentally relevant quantities. Since the molecule undergoes a strong alignment along the polarization axis of the laser field, the ejection of atoms and ions is anisotropic. We have chosen the well known diatomic ion Na-2(+) as a convenient example.