In this contribution, we consider the wave packet dynamics in the dissociation reaction of NaI at different laser powers for both the preparation and the probing. The probing is made for the asymptotic Na fragment as well as the transition-state complex [Na...I]double dagger*. A novel nonlinear behavior at higher intensities is reported and examined here with a new set of experiments. This behavior reflects the change in the absorption cross section along the reaction coordinate and can be quantified using a simple kinetic picture and a classical model of the dynamics.