Rotation and alignment of diatomic molecules and their molecular ions in strong laser fields

A theory of classical rotation and alignment of diatomic molecules with and without permanent dipole moments and of their molecular ions in strong laser fields is developed. The actions of both cw and pulsed laser fields is considered. Conditions under which molecular axes are aligned with the field, which is presumed to be linearly polarized, have been determined. The analysis leads to a conclusion that molecules exposed to ultrashort laser pulses continue to rotate even after the end of the laser pulse. The effect of dynamical chaos on the rotational angular velocity in strong laser field is discussed.