MOLECULAR-EXCITATION BY LARGE-AREA ULTRASHORT PULSES

We have studied numerically the excitation of a model diatomic molecul e by ultrashort pulses which have large envelope areas. In situations where the dynamics of the wave packet during the excitation process is expected to suppress the oscillatory behavior predicted by the area t heorem, we observe a revival of the oscillations due to the freezing o f the wave packet dynamics by fast Rabi oscillations. Furthermore, we show that with hyperbolic secant pulses one can obtain large excitatio n probabilities, but with Gaussian pulses one can keep the excited sta te wave packet reasonably well-defined even when the dynamics imposed by the excited state potential is expected to deform it strongly.