Dynamics and interference of autoionizing wave packets

We extend earlier theoretical work on the creation of autoionizing wave packets by a single laser pulse to the case where the autoionizing states are excited by two or more laser pulses. The calculations are performed using R-matrix methods combined with time-dependent multichannel quantum-defect theory. Atoms or molecules that are coherently excited into autoionizing states emit electrons in a series of pulses. We have found that the phase does not change rapidly across an electron pulse if the laser has little chirp. By choosing the delay between the two laser pulses, we can have the electron wave packets interfere. This interference can be exploited to partially control when the electron will be emitted and to partially control the time dependence of the channel into which it will be ejected. A comparison of the interference of different ejected wave packets gives information about the probability and phase to be initially excited into different channels.