Quantum control of chemical reactions

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 Na-2) 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 Na-2 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.