Laser-induced alignment dynamics of HCN by short intense pulses

The alignment dynamics of HCN in intense laser fields are studied numerically, using time-dependent quantum mechanics. The alignment, with respect to the laser field polarization vector, is measured from the angular distribution of the molecule using the half-angle (theta) 1/2. It is shown that it can be achieved on a sub-picosecond timescale. The role of the vibration of the two molecular bonds is investigated, as well as the effect of the permanent and field-induced dipole moments on alignment.