The single-particle spectrum and its spacing and curvature distributions in rotating heavy nuclei

For the heavy nucleus U-238(92), the influence of the shape parameters and cranking frequency on single-particle energy levels in a rotating system is examined. It has been found that the level spacing distribution and the two kinds of curvature distributions (with respect to the separation distance and cranking frequency, respectively) of levels individually approach those of the Gaussian unitary ensemble (GUE) in different regions of separation distance and cranking frequency. They, however, share a common parameter region in which they are all close to those of GUE, Furthermore, it is suggested that the chaotic motion in a heavy nucleus is possibly realized under the condition of superdeformation and high spin.