Rotational dynamics of a molecular ensemble in the presence of a strong laser field

The rotational dynamics of a molecular ensemble in the presence of a strong laser field is investigated in the framework of the density-matrix approach. The results obtained are compared with the rotation of molecules in a classical ensemble. The thermal molecular motion in the ensemble is taken into account in a model of random collisions, and various values of the relaxation time are considered. The effect of the relaxation process on molecular alignment is analyzed for the laser-pulse action and in the afterpulse regime. The similarity between quantum and classical rotational dynamics of a molecular ensemble is examined.