A test of optimal laser impulsion for controlling population within the Ns=1, Nr=5 polyad of 12C2H2

Optimal control theory has been employed to populate separately two dark states of the acetylene polyad, N-s = 1 and N-r= 5, by indirect coupling via the ground state. Relevant level energies and transition dipole moments are extracted from the experimental literature. The optimal pulses are rather simple. The evolution of the population is shown for the duration of the control process and also for the field-free evolution that follows the control. One of the dark states appears to be a potential target for realistic experimental investigation because the average population of the Rabi oscillation remains high and decoherence is expected to be weak.