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)?