Developments in techniques for production of quantum state-selected atomic and molecular beams

Reviews the use of quantum state selection in atomic and molecular beams. It is suggested that a consequence of the use of supersonic seeded beams - in addition to its motivation of enhancing beam intensity - is the rotational cooling in molecules which takes place very effectively in the expansion region. Pulsed nozzle beams can be even more effective in rotational cooling. A sketch of a highly selective pure-state system, of the Bernstein group is shown. Basically, this is a molecular electric resonance apparatus, but in this system it is used essentially as a source for (vJ) selection in CsF. (Auth.)