"Laser Control of Chemical Reactions: Toward Deciphering Mechanisms and Understanding the Theoretical and Experimental Limits"

Sept 2-7, 2012

Organizing committee:

Goal of the Workshop

Quantum control refers the application of controlled coherent interactions to direct the dynamics of quantum systems.  It is one of the most exciting frontiers in atomic, molecular and optical physics, spanning physics, chemistry and applied mathematics, with excellent interactions between theory and experiment. Within the context of chemical dynamics, the objective is to design specially tailored laser pulses to selectively break bonds in large molecules.  However, the application to many other areas of physics is growing rapidly, including controlling photoionization, photoemission, high harmonic generation, fluorescence quantum yield, laser pulse properties, directional current in semiconductors, controlled deposition and nanolithography, nuclear magnetic resonance, manipulation of ions in traps and neutral atoms in optical lattices, laser cooling, and quantum information, all using optimally shaped pulses.

Despite the great progress in the field, the very first application studied --- the control of photochemical reactions --- has remained elusive. Theoretical studies indicate that at least in simple systems complete control of chemical products should be possible. The experimental reports of control of chemical bond breakage published since 1998 have generated a great deal of excitement but still leave a lot to be desired. For example, a) except in very simple systems (triatomics) there is virtually no understanding of the mechanism by which bond breakage is controlled; b) some of the key experimental results have been a source of controversy, as to whether the interpretation is correct; c) the contrast ratios of competing products in the experiments performed to date is typically between a factor of two and five --- falling far short of complete control. The purpose of this workshop is to bring together theoreticians and experimentalists to provide a critical assessment of our current understanding of this important area and how to move ahead. The focus will be on 1) elucidating mechanism in quantum control in experiments that have already been carried out; 2) surveying existing methods for determining mechanism in laser control, including physically motivated methods as well as mathematically-systematic methods; 3) to provide a critical assessment of the current state of evolutionary algorithms in quantum control --- what we have learned from them and how mechanistic information can be extracted from them; 4) to explore the systematic use of coherent femtosecond optical spectroscopies (particularly coherent multidimensional optical spectroscopies) to probe the quantum dynamics of reacting molecules and multidimensional potential energy surfaces, for the purpose of first principles design of laser pulses to control photochemical reactions; 5) to explore the possibility of exploiting recent breakthroughs in attosecond pulses and control of electron dynamics to influence the outcome of chemical reactions; 6) to assess whether theory really promises complete control of photochemical reactions; if not, what are the limitations, and if so what is required for experiment to achieve this. A related question is to what extent the theoretical limitations on control using weak fields are relaxed in large molecules.