EXTERNAL-FIELD CONTROL OF CONDENSED-PHASE REACTIONS

Control of tunneling in a symmetric double well coupled to a bath via an external field is demonstrated. Optimal control theory is employed to design a laser field which couples to the reaction coordinate and d rives a localized wave packet on the reactant side to the product side at a specified target time tau. Both a very quantumlike system (high barrier) and a low barrier double well are examined; excellent results are obtained for a range of reduced bath viscosities. Analysis of the control fields and corresponding localization dynamics shows that the frequency components of the control field are more or less in resonan ce with eigenstates of the double well and that the laser field enhanc es the natural dynamics of the individual wells. Future extension to m ore complicated models where the held couples to the bath is discussed . (C) 1998 American Institute of Physics.