Quantal Rotation: Molecules and Nuclei


Stefan Frauendorf (Notre Dame U                                                                                                                      


  The motion of a rigid body is a standard subject of classical mechanics. Starting from there, the quantal rotation of molecules is discussed. This talk will review how the indistinguishability of the constituents leads to a partial disappearance of the angular degrees of freedom. 

The rotation of nuclei has been conventionally discussed in analogy with molecular rotation, using a standard interpretation due to Bohr and Mottelson.  Experiments that set nuclei into very rapid rotation (1023cycles/second) have demonstrated that this is actually too narrow a view. Many new phenomena, absent in both molecular and classical rotation, appear, as a consequence of rapid particle alignment, magnetic rotation, chirality and band  termination. They raise the fascinating question: how does spatial orientation come about in system that is  composed of many indistinguishable particles (nucleons)?