3-DIMENSIONAL CRANKING AT FINITE-TEMPERATURE

The rotation of hot triaxial nuclei is studied with the i13/2 model. A single j=13/2 shell in the presence of a triaxial quadrupole potential is rotated in three dimensions and at finite temperature to calculate statistical fluctuations in the orientation of the intrinsic nuclear shape relative to the rotation axis. Calculations are performed with the cranking model under two alternative constraints: (i) the rotational frequency is held constant as the rotation axis is varied, and (ii) the average spin is held constant as the rotation axis is varied. The thermal dependence of the orientation probability distribution is studied for each constraint. The existence of ''tilted'' yrast state solutions is demonstrated at zero temperature for even particle number. These solutions correspond to stable uniform rotation about an axis that lies in a principal plane of the quadrupole potential. The possibility of observing stable tilted solutions in the extended Landau theory of hot rotating nuclei is discussed.