Nuclear orientation by anisotropic collisions

The anisotropic interaction of fast ions with atoms or a solid results in an orientation of the spatial distribution of the orbital angular momenta of excited electronic levels. This orientation of the electronic shell is transfered via hyperfine interaction to the nuclei and a vector polarization of the nuclear spins is observed. Since this kind of fast beam interaction generates an anisotropy in a rather general way, this technique seems to provide a universal source for polarized ions. General concepts of this type of interaction are discussed, and the applications to produce nuclear spin polarized ions and future developments in this field are outlined. (Auth.)