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Rotation-induced time-odd components in the nuclear mean field are analyzed using the Hartree-Fock cranking approach with effective interactions SIII, SkM*, and SkP. Identical dynamical moments J (2) are obtained for pairs of superdeformed bands 151 Tb(2)-152 Dy(1) and 150 Gd(2)-151 Tb(1). The corresponding relative alignments strongly depend on which time-odd mean-field terms are taken into account in the Hartree-Fock equations. PACS number(s): 21.60.-n, 21.60.Ev, 21.60.Jz

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Results of a multidimensional {p2, 7, PA, (O, Z, and A") search for nuclear superdeformed configurations are presented. Calculations based on a realistic deformed average field give a relatively strong dependence of the "super" elongation on the particle number. This dependence is shown to be a cyclic function of the particle number. It originates from the pseudospin and pseudo-SU(3) symmetries which are obeyed approximately in a realistic average field.PACS numbers: 21.10.Gv, 21.60.Fw Nuclear states are commonly called superdeformed if the spatial distribution of nuclear matter is strongly elongated (cf. related harmonic-oscillator structures0. In view of the recent discovery^ of a rotational band built on the superdeformed states in ^^^Dy and extending up to /max ^60, and another one^ in ^^^Ce extending up to /max -52, the prospect of detailed studies of the structure, population, and decay of such bands opens up. The need for their uniform and possibly general classification and abundance scheme becomes apparent.We base our analysis on the deformed Woods-Saxon average field"* and the Strutinsky^ approach in the versions of Andersson et al.,^ Bengtsson and Ragnarsson,^ and Dudek and Nazarewicz.^ We consider the deformation space spanned by the quadrupole iPi.y) and the hexadecapole (^4) degrees of freedom. Nuclear rotation is accounted for by the introduction of the rotational frequency (o in the usual one-dimensional cranking approach (cf., e.g., Ref. 6).Let us summarize the results of our multistep procedure. First the single-particle levels were tabulated versus Pi.y and ^4 at (o=0.The strongest shellstructure effects resulted for axial symmetry, i.e., for /-0°, many of them weakly dependent on p^ in a relatively large /34 range. Therefore the global features of the Woods-Saxon single-particle spectra will be discussed as functions of f32 and displayed along one single trajectory in (^2,/^4) space representative of many nuclei. Systematic detailed calculations showed that the steepest-descent lines in the total-energy surfaces lie close to this trajectory for most of the nuclei considered here. The neutron single-particle levels are displayed along such a trajectory in Fig. 1. The areas of increased level density are shaded. The spectrum exhibits several stripes of low level density. We refer to the stripes as chains of deformed shell closures. Analogous features hold for the proton spectrum and are strikingly similar to those found ^ ^ in the Nilsson model.To suggest a possible origin of the regularities demonstrated in Fig. 1, we introduce the spectrum of the pseudo-oscillator. It is obtained from that of the harmonic oscillator by ignoring all the states which, after introduction of spin-orbit interaction, will give rise to the I'^lmax^^ (intruder) orbitals. We denumerate the remaining levels using the pseudo-oscillator quantum numbers 7V=7V -1, n^-nz, each level carrying (25* + 1)(TV -/I2 + 1) degeneracy (spin s = j).

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Self-consistent solutions for the so-called planar and chiral rotational bands in 132La are obtained for the first time within the Skyrme-Hartree-Fock cranking approach. It is suggested that the chiral rotation cannot exist below a certain critical frequency which under the approximations used is estimated as Planck's omega(crit) approximately 0.5-0.6 MeV. However, the exact values of Planck's omega(crit) may vary, to an extent, depending on the microscopic model used, in particular, through the pairing correlations and/or calculated equilibrium deformations. The existence of the critical frequency is explained in terms of a simple classical model of two gyroscopes coupled to a triaxial rigid body.