  Using the technique of an optical centrifuge, we produce rotational wave
packets which evolve in time along either classical-like or non-classical
trajectories. After releasing O2 and D2 molecules from the centrifuge, we track
their field-free rotation by monitoring the molecular angular distribution with
velocity map imaging. Due to the dispersion of the created rotational wave
packets in oxygen, we observe a gradual transition between "dumbbell"-shaped
and "cross"-shaped distributions, both rotating with a classical rotation
frequency. In deuterium, a much narrower rotational wave packet is produced and
shown to evolve in a truly classical non-dispersing fashion.
