📖 A Mechanical Means of Producing Cold, Slow Beams ofMolecules. A Counter-Revolutionary Concept.

In this work, we describe a method by which to create cold, slow beams of molecules using a rotating supersonic molecular beam source. The supersonic expansion cools the internal temperature of the molecules and the rotor velocity largely cancels the flow velocity of the beam, slowing the beam. Centrifugal action enhances the backing pressure of the supersonic expansion and significantly cools the molecules and further enhances the beam intensity. Theoretical calculations and design specification are presented, followed by extensive experimental results for both supersonic and effusive molecular beams. The latter includes beams of pure gases and seeded beams, where the molecule of interest is further slowed by inverse seeding in a heavy rare gas. Finally, other molecular cooling and trapping techniques are described including experimentally-realized techniques (buffer gas loading, photoassociation of cold atoms, and timed pulsed electric fields) and several new theoretical ideas (e.g. multi-wavelength lasers, laser scooping, intracavity slowing, bichromatic slowing, and reactive scattering).