  The dynamics of non-polar diatomic molecules interacting with a far-detuned
narrow-band laser field, that only may drive rotational transitions, is
studied. The rotation of the molecule is considered both classically and
quantum mechanically, providing links to features known from the heavy
symmetric top. In particular, quantum decoherence in the molecular rotation,
being induced by spontaneous Raman processes, is addressed. It is shown how
this decoherence modifies the rotational dynamics in phase space.
