The symmetries of an antiferromagnetic face-centered-cubic lattice with alternating isospin layers reproduce simultaneously several one- and two-dimensional spin- and isospin-ordered states which have previously been shown to be low energy configurations for a condensed nuclear phase. The face-centered-cubic lattice also shows a precise correspondence with the j-j model and, consequently, the entire nucleon buildup procedure of the independent-particle model. It is concluded that the study of nuclear condensates at normal nuclear densities should begin with the face-centered-cubic configuration.

A simple parametrization of the frequencies of low-energy octupole phonons in spherical and weakly deformed heavy nuclei is given. It is shown that this parametrization substantially simplifies the interpretation of octupole states in the A=70, A=100, and A=120 regions and provides information on the ordering and spacing of single particle orbitals in valence shells in the latter region. Finally, this parametrization is used for an investigation of the nature of the low-lying negative parity states in Ra and Th isotopes.

We analyze the SO(8) model of Ginocchio in the case of an odd number of nucleons and study its properties under group contraction. We obtain an interacting boson-fermion model with parameters arising from the microscopic SO(8) Hamiltonian. Some considerations are made about nuclear supersymmetry.

The usefulness of perturbative expansions in deformed bosons has been limited by difficulties associated with zero-frequency (Goldstone) modes. A method developed earlier by Marshalek and Weneser to overcome these difficulties was restricted to the case in which the broken-symmetry generators commute. The present paper shows how to extend the method to the non-Abelian case of three-dimensional rotation of axially symmetric deformed systems. Application is made to a generic anharmonic Hamiltonian constructed from random-phase-approximation modes.

The complete low energy two-particle spectrum arising from the coupling of the single-particle orbitals with summed energy ($E_{\mathrm{p}+E_{\mathrm{n}}}$) up to 750 keV, and from the coupling of all known proton orbitals up to 1.5 MeV with the ground state neutron, is calculated for the doubly odd deformed nucleus ${}_{}{}^{166}{}_{}{}^{}\mathrm{Ho}$. The bandhead energies, the Gallagher-Moszkowski splitting energies, and the nuclear moment of inertia parameters for deriving the rotational energies are calculated for a zero range residual interaction for each of the 34 possible bands for comparison with the available experimental results from radioactive decay, neutron capture, and particle transfer reaction studies wherein 21 bands have been postulated. Our calculations agree with the characterization of 11 of these bands. We further present evidence for selecting specific $K^{\pi }$ and/or configurations for the remaining 10 bands. Predicted location and character of 13 bands not observed so far are given. Identification of 3 of these bands with known levels is proposed.

The relation between the author’s transport theory approach to the systems with unstable particles and the S-matrix formulation of statistical mechanics is established. Then, the equilibrium characteristics of a classical gas of nucleons, deltas, and pions are studied. The finiteness of the delta decay width is taken into account. It is shown that if one treats the delta isobars as stable particles their number is significantly underestimated at the temperatures smaller than about 60 MeV.

Generating functions are given for the angular momentum states of prescribed seniority of an assembly of identical particles, both for bosons and for fermions. The method is extended for multilevel configurations. Possible applications are discussed.

We report the results of a study of the yrast excitation spectrum for ${}_{}{}^{216}{}_{}{}^{}\mathrm{Rn}$ via the ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$${(}^{14}$C,α2n${)}^{216}$Rn reaction. Measurements of γ-γ coincidences, γ-ray angular distributions, and γ-x-ray coincidences were made. We propose a level spectrum up to $J^{\pi }$${=(10\mathrm{}}^{+}$) which does not exhibit the alternating parity structure observed in several isotopes of radium and thorium. From an examination of information on ${}_{}{}^{216}{}_{}{}^{}\mathrm{Rn}$ and the neighboring nuclei, we can tentatively determine that the radon isotopes of masses 216 to 222 and the N=128 isotones ${}_{}{}^{216}{}_{}{}^{}\mathrm{Ra}$ and ${}_{}{}^{218}{}_{}{}^{}\mathrm{Th}$ define a lower mass boundary of a region beyond which static intrinsic reflection asymmetric shapes may exist in the nuclear ground states.

The photoactivation of ${}_{}{}^{111}{}_{}{}^{}\mathrm{Cd}$ with a ${}_{}{}^{60}{}_{}{}^{}\mathrm{Co}$ source and a set of intervening iron absorbers has been studied. The induced activity of ${}_{}{}^{111}{}_{}{}^{}\mathrm{Cd}_{}^{\mathrm{m}}{}_{}{}^{}$ is interpreted completely by assuming resonant excitation of the 1330 keV state followed by decay to the isomeric state, thereby discounting the necessity of any ‘‘nonresonant’’ photoexcitation process.

Alpha particles have been measured in coincidence with both projectile-like fragments (Z=5–8) and light fragments (Z=3–4) in the reactions of 35 MeV/nucleon ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ with ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$. These results provide an extension of previous systematics studying the evolution of nonequilibrium emission of α particles from reactions at 6 to 20 MeV/nucleon. Two nonequilibrium components can be identified: one consists of beam velocity α particles and the other consists of intermediate velocity α particles. Compared to lower bombarding energies, no drastic change in the reaction mechanism has been observed at the Fermi energy.

The ${}_{}{}^{81}{}_{}{}^{}\mathrm{Kr}_{}^{\mathrm{m}}{}_{}{}^{}$ electron capture branching ratio to ${}_{}{}^{81}{}_{}{}^{}\mathrm{Br}$ has been remeasured and found to be (2.26±0.32)×${10}^{\mathrm{-}5}$ with a logft value of 4.93±0.06. This result is 2.5 times smaller than a previous measurement and implies a similar reduction in the rate for solar neutrino capture in an ${}_{}{}^{81}{}_{}{}^{}\mathrm{based}$ detector.

We propose a non-‘‘hedgehog’’ ansatz for the pion in two types of quark models, numbers I and II, which are based on the linear and nonlinear σ model, respectively. With the new ansatz, we find the equations of motion can be solved exactly in model I and approximately in model II. We show that by introducing the ω-quark interaction, the predictions of $g_A$, $g_{\pi \mathrm{NN}}$, and ${\mu }_{\mathrm{p}}$ are significantly improved in a case within model II.

Bandhead energy calculations for the low-lying two-quasiparticle states in the doubly-odd nucleus ${}_{}{}^{168}{}_{}{}^{}\mathrm{Tm}$ have been carried out based on the quantitative evaluation of the zero-range residual neutron-proton interaction. These calculations lead to the configurational assignment $0^{+}${(7/2${)}^{+}$[404${]}_{p-(7/2\mathrm{}{)}^{+}[633{]}_n\}}$ for the recently established 17 keV excited state in this nucleus. The experimental low-lying unassigned states in ${}_{}{}^{168}{}_{}{}^{}\mathrm{Tm}$, taken together with the known band structure for this configuration in the neighboring nuclei, suggest five rotational states with $J^{\pi }$${=1\mathrm{}}^{+}$ to $5^{+}$ built on the $K^{\pi }$${=0\mathrm{}}^{+}$ bandhead at 17 keV.

The location of the high spin members of the ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ $K^{\pi }$${=0\mathrm{}}_4^{+}$ rotational band is discussed by examining the low energy properties of the unique optical potential describing ${}_{}{}^{16}{}_{}{}^{}(\mathit{\alpha }$,α) elastic scattering on a broad range of energies and angles. In particular, the last $J^{\pi }$${=10\mathrm{}}^{+}$ member is predicted to lie at about 29 MeV excitation energy and to be very broad, in contrast with the current expectations. It is suggested that the measurement of the α${+\mathrm{}}^{16}$O fusion excitation function in the relevant energy range could provide a clear signature of the presence of this state. We discuss the implications of our results for the lower spin attributions to this band.

New neutron-rich isotopes of several rare-earth elements have been identified using on-line mass separation. The observed decay rates of K x rays in the mass separated fractions for which 153≤A≤162, together with the associated γ-decay spectra, provided direct isotopic identifications. New isotopes observed, with values of their half lives given in parentheses, are ${}_{}{}^{153}{}_{}{}^{}\mathrm{Pr}$ (4.3±0.2 s), ${}_{}{}^{155}{}_{}{}^{}\mathrm{Nd}$ (8.9±0.2 s), ${}_{}{}^{156}{}_{}{}^{}\mathrm{Nd}$ (5.47±0.11 s), ${}_{}{}^{157}{}_{}{}^{}\mathrm{Pm}$ (10.90±0.20 s), ${}_{}{}^{158}{}_{}{}^{}\mathrm{Pm}$ (4.8±0.5 s), and ${}_{}{}^{162}{}_{}{}^{}\mathrm{Eu}$ (10.6±1.0 s). In addition, we have confirmed recent reports of the observation of ${}_{}{}^{153}{}_{}{}^{}\mathrm{Nd}$ (28.9±0.4 s), ${}_{}{}^{154}{}_{}{}^{}\mathrm{Nd}$ (25.9±0.2 s), ${}_{}{}^{156}{}_{}{}^{}\mathrm{Pm}$ (26.70±0.10 s), ${}_{}{}^{159}{}_{}{}^{}\mathrm{Sm}$ (11.37±0.15 s), and ${}_{}{}^{160}{}_{}{}^{}\mathrm{Sm}$ (9.6±0.3 s). These half-life values are compared to the reuslts of theoretical predictions.

We have investigated possible exotic dipole resonances for finite nuclei in the Walecka model by performing a small amplitude time-dependent mean-field calculation with an ansatz based on a few collective degrees of freedom. We find that the frequencies of such resonances are several hundred MeV and that the resonances are dominated by the mesonic degrees of freedom.

We show that the SU(3) limit of the U(16) model used to describe asymmetric shape deformation in even-even nuclei may be simply extended to odd-mass nuclei. The extension results in decoupling parameters with opposite signs in opposite-parity bands. We discuss the model in connection with the spectrum of ${}_{}{}^{255}{}_{}{}^{}\mathrm{Ra}$.

The production of photons from heavy-ion collisions at intermediate energies is studied in the model based on the Boltzmann-Uehling-Uhlenbeck equation. Taking into account photon production from nucleon-nucleon collisions, the theoretical results are in reasonable agreement with the experimental data at 40 MeV/nucleon, but cross sections are smaller by about a factor of five, compared to experiment at 35 MeV/nucleon. The results at these energies show no dependence on the nuclear equation of state.