The longitudinal response functions of three-body nuclei are obtained from the inversion of their integral transforms with a Lorentz kernel. The full dynamics of initial and final states is treated within this method. Results are in excellent agreement with those of previous quite different calculations. A comparison with experimental data is also presented.

High spin states of ${}_{}{}^{65}{}_{}{}^{}\mathrm{Ge}$ have been investigated via the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$${(}^{28}$Si,2pn${)}^{65}$Ge reaction at 93 MeV beam energy. A level scheme containing 36 new transitions and 20 new levels could be established on the basis of γγ and γγn coincidences, γ-angular distributions and γ-linear polarization measurements. The aim of the work was to study the softness with respect to octupole deformation as theoretically predicted for the lightest Ge and Se isotopes. We could definitely show that the excitation energy of the 15/$2^{\mathrm{-}}$ state (i.e., the coupling of the ${\mathit{g}}_{9/2}$ neutron to the $3^{\mathrm{-}}$ octupole state in ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ge}$) is not strongly lowered in comparison to the neighboring Ge nuclei, but fits reasonably well into the trend of smoothly rising energy with decreasing neutron number. Consequently, it should be concluded that the lightest Ge isotopes do not display enhanced octupole correlations, at least in the energy range of ${\mathit{E}}_{\mathit{x}}$≤5 MeV.

Lifetimes for the lowest three transitions in the nucleus ${}_{}{}^{120}{}_{}{}^{}\mathrm{Xe}$ have been measured using the recoil distance technique. Our data indicate that the lifetime for the $2_1^{+}$→$0_1^{+}$ transition is more than a factor of 2 lower than the previously adopted value and is in agreement with more recent measurements performed on this nucleus. The theoretical implications of this discrepancy and the possible reason for the erroneous earlier results are discussed. All measured lifetimes in ${}_{}{}^{120}{}_{}{}^{}\mathrm{Xe}$, as well as the systematics of the lifetimes of the $2_1^{+}$ states in Xe isotopes, are compared with predictions of various models. The available data are described well by the fermion dynamic symmetry model (FDSM).

The magnetic moment of the ${10}^{+}$ isomeric state of ${}_{}{}^{132}{}_{}{}^{}\mathrm{Ba}$ at 3115 keV was measured as g=-0.156(11). A 60 MeV ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ beam from the Koffler Pelletron accelerator at the Weizmann Institute was used in the reaction ${}_{}{}^{124}{}_{}{}^{}\mathrm{Sn}$${(}^{12}$C,4n${)}^{132}$Ba. The measured g factor confirms the (ν${\mathit{h}}_{11/2}$${)}^{\mathrm{-}2}$ configuration of the level. The result is compared with other g factors in neighboring N=76 isotones.

The anharmonicity of octupole vibrations is deduced over a wide range of Z and A through the examination of summed B(E3)↑ values for all $3^{\mathrm{-}}$ states in a given nuclide versus the centroid energy for those states. Data obtained with the (p,${\mathit{p}}^{\prime }$), (d,${\mathit{d}}^{\prime }$), and (α,${\mathrm{\alpha }}^{\prime }$) reactions are used, as opposed to an earlier study based on Coulomb excitation and lifetime data. Results of the new analysis support earlier observations of significant anharmonicity, but leave open the possibility of greater harmonicity than was previously supposed. Fits to the experimental data are discussed within the framework of the hydrodynamical model and possible mechanisms for the observed behavior are suggested.

In a series of ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ti}$ bombardments of ${}_{}{}^{144}{}_{}{}^{}\mathrm{Sm}$ the decay energy of the ${}_{}{}^{189}{}_{}{}^{}\mathrm{Bi}_{}^{\mathit{m}}{}_{}{}^{}$ (π${\mathit{s}}_{1/2}$) α transition that proceeds to the (π${\mathit{s}}_{1/2}$) ground state of ${}_{}{}^{185}{}_{}{}^{}\mathrm{Tl}$ was measured to be 7.30(4) MeV. This result establishes the excitation energy of ${}_{}{}^{189}{}_{}{}^{}\mathrm{Bi}_{}^{\mathit{m}}{}_{}{}^{}$ as 190(40) keV rather than the adopted 92(10)-keV value. Our data indicate a leveling off in excitation energy at N≊106 for the ${\mathit{s}}_{1/2}$ intruder state in the odd-A Bi isotopes rather than a continued drop at that neutron number as inferred by Coenen et al. in their discussion of intruder state systematics in the Pb region. Consequences of this discrepancy for the adopted excitation energy of the π${\mathit{s}}_{1/2}$ isomer in ${}_{}{}^{187}{}_{}{}^{}\mathrm{Bi}$ are discussed.

The result of the study of the high-spin states of the ${}_{}{}^{102}{}_{}{}^{}\mathrm{Ru}$ using the incomplete fusion reaction of ${}_{}{}^{100}{}_{}{}^{}\mathrm{Mo}$${(}^7$Li,[p,d,t]xnγ) at 49 MeV is presented. The experimental data are the result of particle–γ-γ coincidence and in-plane out-of-plane anisotropy measurements. The ground state band is extended up to ${\mathit{E}}_{\mathit{x}}$=5.719 MeV (${\mathit{J}}^{\mathrm{\pi }}$=${16}^{+}$), and two other negative parity bands are also extended to higher spins up to ${\mathit{E}}_{\mathit{x}}$=4.707 (${\mathit{J}}^{\mathrm{\pi }}$=${13}^{\mathrm{-}}$) and ${\mathit{E}}_{\mathit{x}}$=4.615 MeV. Shape coexistence in ${}_{}{}^{102}{}_{}{}^{}\mathrm{Ru}$ at lower excitation energies was investigated using a two-band mixing model. The high-spin features of ${}_{}{}^{102}{}_{}{}^{}\mathrm{Ru}$ are compared with the prediction of the cranked Nilsson model.

We investigate the consequences on the order/chaos transition of replacing the scalar rotational energy of the particles-rotor model by a one-body cranking term. The nearest-neighbor distribution of energy levels and the spectral rigidity are studied as a function of the spin or cranking frequency, respectively. Exact energies for our statistical analyses are obtained from a full diagonalization of a many-body Hamiltonian with two-body forces for six particles in an ${\mathit{i}}_{13/2}$ shell coupled to a deformed core. In this model, the competing physical effects (two-body interaction strength, quadrupole deformation, and moment of inertia) are easily parametrized and studied. The dependence of the chaoticity on model parameters reveals the stabilizing influence of a large quadrupole deformation. For low spins, the considerable effects of the (effectively two-body) recoil term give significant differences between the two descriptions.

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 ${\mathcal{J}}^{\mathrm{}\left(2\right)\mathrm{}}$ are obtained for pairs of superdeformed bands ${}_{}{}^{151}{}_{}{}^{}\mathrm{Tb}$(2)${\mathrm{-}}^{152}$Dy(1) and ${}_{}{}^{150}{}_{}{}^{}\mathrm{Gd}$(2)${\mathrm{-}}^{151}$Tb(1). The corresponding relative alignments strongly depend on which time-odd mean-field terms are taken into account in the Hartree-Fock equations.

The model of an α cluster orbiting a closed shell core provides a highly successful description of low lying bound and resonant states of ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ and has been successfully extended to ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ti}$ by various authors. This description is closely related to α scattering from the relevant closed shell core, and although the scattering has previously been reasonably well reproduced with a local optical model potential, few attempts have been made to link the two phenomena. In this paper, a universal α-core interaction is given which describes the spectra, B(E2↓) transition strengths, α-decay widths, and differential elastic scattering cross sections for the systems corresponding to ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$${=}^{16}$O+α and ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ti}$${=}^{40}$Ca+α. This potential has only a single free parameter, the radius, whose value is kept fixed for each nucleus.

A two-parameter model is constructed considering the pairing correlation between the normal and abnormal parity states based on the fermion dynamical symmetry model (FDSM). Under reasonable approximations this model can be deduced from a Hamiltonian distinguishing the protons and neutrons. The mechanism of the stretching effect is contained in this model and shown by the numerical results. More importantly, the numerical calculations of this model show that the data of the yrast lines of 15 typical rotational nuclei in the actinide region are fitted in a very high quality.

A unified description of the low lying excited states of the ground bands of even-even nuclei throughout the Periodic Table is obtained. A new variable in the geometrical part of the interaction characterizing the different types of collective modes is evaluated and analyzed. A phenomenological formula for the dynamical coefficient of the interaction, depending on the nuclear shell quantum numbers, is derived. A good agreement between the so-obtained theoretical ground band energies and the experimental ones is obtained for 927 low lying states of 271 nuclei from five major shells.

A new two-parameter formula for the rotational spectra of well-deformed nuclei is presented for the first time. The formula is deduced from experimental level systematics and alternatively from nuclear hydrodynamics. Comparisons with a great number of rotational spectra of even-even nuclei in rare-earth and actinide regions show that the formula can give a best fitting to the experimental data.

Spontaneous-fission half-lives of the heaviest nuclei are analyzed in a multidimensional deformation space. They are calculated in a dynamical approach, without any adjustable parameters. The potential energy is obtained by the macroscopic-microscopic method and the inertia tensor by the cranking method. The action integral is minimized by a variational procedure. Even-even nuclei with proton number Z=104–114 and neutron number N=142–176 are considered. The results reproduce existing experimental data rather well. Relatively long half-lives are predicted for many unknown nuclei, sufficient to detect them if synthesized in a laboratory.

The low lying levels in N=50 isotones have been well described within the shell model framework. These calculations were performed assuming an inert neutron core and the valence protons occupying either the (${\mathit{p}}_{1/2}$,${\mathit{g}}_{9/2}$) or (${\mathit{f}}_{5/2}$,${\mathit{p}}_{3/2}$,${\mathit{p}}_{1/2}$,${\mathit{g}}_{9/2}$) orbits. With the advent of multidetector arrays the level schemes of these nuclei have been extended to high spin regimes (J=20-25ħ). The inclusion of neutron core excitation (neutron particle-hole excitation across the N=50 shell gap) was essential to adequately describe these observed higher angular momentum states. Calculations involving neutron particle-hole excitation across the N=50 shell gap, coupled to the lower valence proton configurations, were not feasible due to computational limitations. This paper describes a truncation scheme devised to perform large basis shell model calculations. The level sequences observed in the N=50 isotones ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$, ${}_{}{}^{93}{}_{}{}^{}\mathrm{Tc}$, ${}_{}{}^{94}{}_{}{}^{}\mathrm{Ru}$, and ${}_{}{}^{95}{}_{}{}^{}\mathrm{Rh}$ are interpreted on the basis of the shell model calculations in the configuration space ${\mathit{f}}_{5/2}$, ${\mathit{p}}_{3/2}$, ${\mathit{p}}_{1/2}$, ${\mathit{g}}_{9/2}$ for the protons and ${\mathit{p}}_{1/2}$, ${\mathit{g}}_{9/2}$, ${\mathit{g}}_{7/2}$, ${\mathit{d}}_{5/2}$, ${\mathit{d}}_{3/2}$, ${\mathit{s}}_{1/2}$ for the neutrons. The excitation of a ${\mathit{g}}_{9/2}$ neutron across the N=50 shell, into the next major oscillator shell describes the observed higher angular momentum states in these nuclei.

Differential cross sections for the elastic scattering of 350 MeV ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ from ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ have been measured. The characteristics of the angular distributions are very similar to those of 318 MeV ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ scattering from the same targets, with diffractive oscillations at the forward angles and smooth exponential falloff, attributed to the dominance of far-side scattering, at the larger angles. The peak-to-valley ratios of the oscillatory structure are similar to those for ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, indicating that the ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ ground-state quadrupole moment has no discernible effect on the cross sections. Like the ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ data, the ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ data define unique phenomenological optical-model potentials. Double-folding model potentials calculated from fundamental nucleon-nucleon interactions also provide reasonably good fits to the experimental data.

We have experimentally studied small impact parameter heavy-ion collisions in the (nearly) symmetry entrance channels ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${+}^{12}$C, ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$${+}^{27}$Al, ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$${+}^{45}$Sc, ${}_{}{}^{84}{}_{}{}^{}\mathrm{Kr}$${+}^{93}$Nb, and ${}_{}{}^{129}{}_{}{}^{}\mathrm{Xe}$${+}^{139}$La, each at many intermediate beam energies. The results from a number of analyses based on a projection of the ‘‘shapes’’ of the experimental events called the sphericity are presented. Comparisons of the relative efficiencies of various experimental methods for the selection of central events are made. The importance of autocorrelations between the sphericity and the various impact-parameter–dependent variables is evaluated. Searches for beam energy-dependent transitions from sequential binary disassembly to multifragmentation in the central events are described. Comparisons to dynamic and hybrid model code calculations will be discussed. The average sphericities of the intermediate mass fragments (IMF’s, for which 3≤Z≲20), are presented. The possibility that the IMF emission occurs following the formation of transient toroidal or disk-like geometries in the central events is explored. Increases in the average sphericities of the central events for increasing beam energies are observed which is attributed to transitions from sequential binary disassembly to multifragmentation. The transitional beam energies for the central ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$${+}^{45}$Sc, ${}_{}{}^{84}{}_{}{}^{}\mathrm{Kr}$${+}^{93}$Nb, and ${}_{}{}^{129}{}_{}{}^{}\mathrm{Xe}$${+}^{139}$La reactions are near ∼50, ∼40, and ∼40 MeV/nucleon, respectively.

High energy photon emission accompanying the spontaneous fission of ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$ is measured for different mass splits. The photon yields up to an energy of 20 MeV are obtained at several angles relative to the fission direction. Statistical model calculations are used to interpret the data. The photon yield is found to be very sensitive to the initial excitation energy sharing among the daughter nuclei and to their level density parameters. Using experimentally extracted level densities obtained from neutron evaporation measurements, the photon yield is well described by calculations for all mass splits.

A complete set of analyzing powers (i${\mathrm{T}}_{11}$, ${\mathrm{T}}_{20}$, ${\mathrm{T}}_{21}$, and ${\mathrm{T}}_{22}$) are reported for the elastic scattering of 50 MeV ${}_{}{}^6{}_{}{}^{}\to$ by ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$. They are as large as or larger than those measured earlier for 30 MeV ${}_{}{}^6{}_{}{}^{}\to$. A combined optical model analysis of both energies shows ${\mathrm{T}}_{21}$ to arise from the tensor interaction, ${\mathrm{T}}_{20}$ to involve a combination of tensor and J-dependent interactions, and i${\mathrm{T}}_{11}$ to be the most complicated, arising from an explicit spin-orbit, as well as tensor and J-dependent interactions. A coordinate transformation of the data and calculations, suggested in the earlier work of Hooton and Johnson, provides the clearest evidence for the need of a tensor interaction to describe ${}_{}{}^6{}_{}{}^{}\to$ scattering. Examining the optical model calculations in terms of transferred angular momentum amplitudes provides further insight into the role played by each interaction. Also presented are the analyzing powers for the ${}_{}{}^4{}_{}{}^{}\mathrm{He}$${(}^6$Li${,}^4$He) polarimeter reaction at this higher bombarding energy.

It is demonstrated that low-lying collective bands in deformed nuclei are strongly populated by quasielastic heavy ion transfer reactions at near barrier energies. The ${}_{}{}^{161}{}_{}{}^{}\mathrm{Dy}$${(}^{61}$Ni${,}^{62}$Ni${)}^{160}$Dy and ${}_{}{}^{161}{}_{}{}^{}\mathrm{Dy}$${(}^{61}$Ni${,}^{60}$Ni${)}^{162}$Dy reactions at a beam energy of 270 MeV have been studied using a particle-γ technique. Significant population of sidebands in ${}_{}{}^{160}{}_{}{}^{}\mathrm{Dy}$ was observed, particularly the S band built upon the [ν(${\mathit{i}}_{13/2}$)${]}^2$ configuration and the ${\mathit{K}}^{\mathrm{\pi }}$=$1^{\mathrm{-}}$, $2^{\mathrm{-}}$, and γ bands. For ${}_{}{}^{162}{}_{}{}^{}\mathrm{Dy}$ the only sideband significantly populated was the γ band.