The photoassociation processes via the pump-dump scheme for the heternuclear (Na + H NaH) and the homonuclear (Na + Na -> Na-2) molecular systems are studied, respectively, using the timedependent quantum wavepacket method. For both systems, the initial atom pair in the continuum of the ground electronic state (X-1 Sigma(+)) is associated into the molecule in the bound states of the excited state (A(1)E(+)) by the pump pulse. Then driven by a time-delayed dumping pulse, the prepared excited-state molecule can be transferred to the bound states of the ground electronic state. It is found that the pump process can induce a superposition of the rovibrational levels broken vertical bar v, j) on the excited state, which can lead to the field-free alignment of the excited-state molecule. The molecular alignment can affect the dumping process by varying the effective coupling intensity between the two electronic states or by varying the population transfer pathways. As a result, the final population transferred to the bound states of the ground electronic state varies periodically with the delay time of the dumping pulse. (C) 2015 AIP Publishing LLC.
展开▼
