Phase-tailoring molecular wave packets to time shift their dynamics

Time shifting (up to a global arbitrary phase) the dynamics of molecular wave packets, i.e, |Ψ(t)〉→|Ψ(t−tshift)〉, is demonstrated using a high degree of state selective coherent phase control with shaped femtosecond laser pulses. The benchmark system for the present work is the lithium dimer molecule. The phase-tailored Li2 wave packets are composed of several rovibrational states of the electronic E 1 Σ g + shelf state excited from a single rovibrational level (selected using a cw laser) of the A 1 Σ u + state. The time-shifting operation has implications for the experimental implementation of coherent control, as well as for the use of the control ability to study coherent configurations and dynamics that otherwise would be difficult (sometimes impossible) to access experimentally. This is due, for example, to dephasing and/or depopulation of the wave packet in combination with long recurrence times. One such inaccessible coherent configuration of the present Li2 wave packets corresponds to the global maximum of their ionization yield (as probed in the present experiment).