Quantum decoherence in the rotation of small molecules

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, induced by spontaneous Raman processes, is addressed. It is shown how this decoherence modifies the rotational dynamics in phase space.