Making the best of mixed-field orientation of polar molecules: A recipe   for achieving adiabatic dynamics in an electrostatic field combined with   laser pulses
  We have experimentally and theoretically investigated the mixed-field orientation of rotational-state-selected OCS molecules and we achieve strong degrees of alignment and orientation. The applied moderately intense nanosecond laser pulses are long enough to adiabatically align molecules. However, in combination with a weak dc electric field, the same laser pulses result in nonadiabatic dynamics in the mixed-field orientation. These observations are fully explained by calculations employing, both, adiabatic and non-adiabatic time-dependent models. 
Jens H. Nielsen, Henrik Stapelfeldt, Jochen K\"upper, Bretislav   Friedrich, Juan J. Omiste and Rosario Gonz\'alez-F\'erez
physics.chem-ph quant-ph