Mechanisms for laser control of chemical reactions

During the past several years, a new technique for realistic simulations of the interaction of light with matter has been developed and employed. Recent simulations of laser pulses interacting with molecules clearly demonstrate the potential for control of chemical reactions through various mechanisms, which include the following: (i) excitation of electrons to states that have different bonding properties; (ii) control of electron populations through a coherent pump-pulse, control-pulse sequence; and (iii) control of molecular vibrations through a pump-control sequence. Significant chemical insights are gained when one can watch a realistic animation of species interacting and reacting. One can monitor the time evolution of electronic states and their occupancy, as well as the motion of the atoms. One can also observe the evolution from reactants to products through transition states. Finally, one can determine how this evolution is affected by the various properties of the laser pulses, including intensity, duration, phase, and the interval between pulses.