Moshe Shapiro and Paul Brumer
Coherent control provides a quantum-interference based method for controlling chemical reactions. This theory, and its applications to a variety of processes, including branching photodissociation reactions (of such systems as IBr, DOH and Na2) and symmetry breaking (in such molecules as H2O) leading to the possibility of asymmetric synthesis of chiral products, are reviewed. Computations based on the control scenarios amply demonstrate that a wide range of yield control is possible under suitable laboratory conditions and a recent experiment on the control of the Na(3d)/Na(3p) product ratio in the Na2 two-photon dissociation reviewed here proves this point. Theoretical suggestions for controlling bimolecular exchange reactions and other collisional events, via intervention during the collision event (laser catalysis), or before it (pre-reaction control), are discussed.