The effects of the pump intensity, the wavelength and the pulse width on the state populations of the three-level ladder K₂ molecule driven by intense femtosecond pump-probe pulses are investigated by employing the time-dependent wave packet approach and are thus quantified. The Rabi oscillation is affected by the pump intensity, the wavelength and the pulse width, and its variation results in a periodical change of the populations in the ground state and the excited state. Quantifying their effects on the population of the excited state verifies the periodical nature and shows that the frequency varies with the increasing pump intensity and pulse width. The results illustrate that the needed population in the electronic state of interest can be obtained by controlling these parameters, which provides some important basis for light manipulation of molecular processes.

time-dependent wave packet approach  /  three-level K₂ molecule  /  state populations  /  Rabi oscillation