Optimal design of external fields for controlling molecular motion: application to rotation

A general discussion of quantum controllability leads to the specific focus of this work, namely the use of tailored radiation to excite rotational states, either specific |JM〉 states or superposition states which correspond to a high degree of molecular orientation. It is shown that starting from the |00> state it is in principle possible to produce any eigenstate or superposition state given a long enough pulse and specific examples are presented. Highly ordered states, which are useful in a variety of spectroscopic applications, can be prepared by realistic tailored microwave fields.