MULTIPRODUCT COHERENT CONTROL OF PHOTODISSOCIATION VIA 2-PHOTON VERSUS 2-PHOTON INTERFERENCE

We show that the branching ratios into two or three channel photodisso ciation products can be controlled by a novel resonant two-photon vs t wo-photon coherent control scenario. The method allows for control eve n when the initial molecular system is in a mixed state, e.g., in ther mal equilibrium, a significant advance for controlling reactions. Esse ntial to the technique is the phase locking between different frequenc ies which results in cancellation of incoherences due to laser phase j umps. Reduction of uncontrolled background contributions also obtains. The scenario is demonstrated computationally on Na2 photodissociation , where a wide range of control is achieved over branching into two pr oduct channels [Na (3s) + Na (4s) vs Na (3s) + Na (3p)] at lower energ ies and over three product channels at energies above the Na (3s) + Na (3d) threshold.