Optimal control of rotational motions in dissipative media

We apply optimal control theory to explore and manipulate rotational wavepacket dynamics subject to a dissipative environment. In addition to investigating the extent to which nonadiabatic alignment can make a useful tool in the presence of decoherence and population relaxation, we use coherent rotational superpositions as a simple model to explore several general questions in the control of systems interacting with a bath. These include the extent to which a pure state can be created out of a statistical ensemble, the degree to which control theory can develop superposition states that resist dissipation, and the nature of environments that prohibits control. Our results illustrate the information content of control studies regarding the dissipative properties of the bath and point to the strategies that optimize different targets in wavepacket alignment in nonideal environments. As an interesting aside, the method is used to illustrate the limit where the coherence-based approach to molecular alignment converges to traditional incoherent approaches. (C) 2008 American Institute of Physics.