Efficient transfer of inversion doublet populations in deuterated ammonia using adiabatic rapid passage

We demonstrate the efficient transfer of population from the upper to the lower inversion level within the rotational ground state of para-ND 3 . A packet of ND 3 molecules is velocity controlled and state selected using a Stark decelerator, and subsequently transferred with 93% efficiency using the principles of adiabatic rapid passage. Transitions are induced using microwave chirps both under zero-field conditions as well as in the presence of an electric field to probe M J -resolved transition efficiencies. Simulations of the transfer efficiencies based on the von Neumann equation, taking all hyperfine transitions into account, showed excellent agreement with experimental observations.