Population transfer of the Na2 molecule via continuum state

The population transfer between the different electronic states through the ionization continuum state is studied for the Na2 molecule using the quantum wave packet method. The population evolutions of the initial A1Σu+ state, the target 21Πg state and the ionization continuum 2Σg+ state with time are discussed in detail. The time-dependent photoelectron energy spectra are calculated. It is demonstrated that the population can be efficiently transferred from the A1Σu+ state to the 21Πg state via the 2Σg+ state by properly choosing the intensities and the detunings of the pump and Stokes pulses. The effects of one-photon detuning and molecular rotation and alignment on the population transfer are also discussed.