Bond breaking in light-induced potentials

We study the photodissociation of ICl- under moderately strong (TW/cm(2)) and short (below picosecond) laser pulses. Using a single resonant pump pulse, the photodissociation spectra shows two barely overlapping bands corresponding to Frank-Condon excitation and dissociation in two electronic states. By adding a nonresonant stronger control pulse we show that (1) the photodissociation bands can be blueshifted and (2) the asymptotic state of the fragments depends on the chosen pulse sequence. If the pump pulse precedes the control pulse or the control pulse straddles the pump pulse, the outgoing wave packet has components in the two dissociation channels, whereas if the control pulse precedes the pump pulse, the photodissociation proceeds selectively in a single channel.