We now examine how the system reaches the steady-state regime after the onset of an incident field amplitude with a rise time of 5 fs, during which the pump vertically projects the ground vibrational state onto the excited electronic potential energy surface. After propagating the coupled Maxwell-Schrödinger equations ( ) and ( ), we find that the system quickly reaches a plateau under these effectively CW conditions In Fig. , we study the resulting ensemble average nuclear dynamics in the excited electronic state and plot over the first 250 fs. At short times, the peak in the nuclear wavepacket appears at 5 a.u. indicating the Frank-Condon transition. At later times, the peak remains at the same coordinate due to continuous pumping from the ground electronic state, but the tail begins to increase to larger distances as the wavefunction spreads over the dissociative potential surface. As a practical definition, we regard the system as reaching "steady state" when the R probability flux at 30 a.u. defined as (15) no longer depends on time. For the range of parameters considered, this situation is reached at about 450 fs.