A MACROSCOPIC MODEL OF NUCLEAR ROTATION

We have formulated a statistical model of nuclear properties that comb ines the Thomas-Fermi assumption of two fermions per h(3) of phase spa ce with an effective interaction between the nucleons. The model has b een employed in the calculation of nuclear masses and density distribu tions. The initial calculations assumed spherical symmetry but a later extension to three dimensions permits the calculation of fission sadd le-point shapes and the corresponding fission barriers. It is also pos sible to include angular momentum and we have constructed an extension of the model which describes approximately ground-state, superdeforme d and fission-isomeric rotational bands of even-even nuclei. The model is based on a three-term energy expression corresponding to: a) a rig id rotation of part of the nucleus, b) the energy of initially counter -rotating gyroscopes that the overall rotation gradually aligns in the direction of the total angular momentum, and c) a potential energy re sisting such alignment. The model can be used for a macroscopic descri ption of the angular momentum dependence of nuclear fission barriers.