Magnetic moments around the Z=40 shell closure have been established using nuclear magnetic resonance on oriented nuclei in iron. From the resonance frequencies we established ‖μ${(}^{91}$Y;9/$2^{+}$)‖=6.01${(}_{\mathrm{-}15}^{+31\mathrm{}}$)${\mathrm{\mu }}_{\mathit{N}}$, ‖μ${(}^{95}$Zr; 5/$2^{+}$)‖=1.103(23)${\mathrm{\mu }}_{\mathit{N}}$, ‖μ${(}^{97}$Nb;9/$2^{+}$)‖=6.153(5)${\mathrm{\mu }}_{\mathit{N}}$. The results obtained are discussed in the framework of particle-core coupling and, in more detail, using the Nilsson deformed single-particle model. It is shown that for certain deformation regions the measurement of the magnetic moment can give information on the nuclear quadrupole deformation.

The decay of ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ at high excitation energies has been investigated by the interaction of a ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ beam with ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ targets. Coincident heavy-ion–heavy-ion detection allowed for the study of the ${}_{}{}^{12}{}_{}{}^{}\mathrm{-}_{}^{12}{}_{}{}^{}$C and ${}_{}{}^{16}{}_{}{}^{}\mathrm{-}_{}^8{}_{}{}^{}$Be decay modes of ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$. No evidence for these processes was found in the interaction of the beam with the ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ target. The ${}_{}{}^{12}{}_{}{}^{}\mathrm{-}_{}^{12}{}_{}{}^{}$C relative energy spectra measured via the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$${+}^{12}$C reaction provide indication for the excitation of a few selected ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ states around 30 MeV. Spins as high as 12ħ, deduced from the angular correlations, are consistent with a quasimolecular nature of these states.

The structure of ${}_{}{}^{101}{}_{}{}^{}\mathrm{Tc}$ has been studied using the ${}_{}{}^{100}{}_{}{}^{}\mathrm{Mo}$${(}^7$Li,α2n) reaction at 49 MeV. Both particle-γ and particle–γ-γ coincidence experiments were performed. The intensities of γ rays both in and out of the reaction plane were measured to obtain information on the ΔI of the transitions. A new band based on the π${\mathit{g}}_{9/2}$ configuration was identified for the first time. To investigate the shape coexistence or configuration dependent deformation in this nucleus, interacting-boson-fermion-model and cranked shell-model calculations have been performed. Cranked shell-model calculations were used to interpret the states at higher excitation energies.

We have measured the scattering of 375-MeV ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$ ions by isotopes of ${}_{}{}^{204,206,208}{}_{}{}^{}\mathrm{Pb}$ to investigate the isospin character of transitions to low-lying $2^{+}$ and $3^{\mathrm{-}}$ states. The data were analyzed using the deformed optical potential model. The $2^{+}$ collective strength, which is concentrated in a single state at 4.085 MeV in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$, is observed to fragment in both ${}_{}{}^{204}{}_{}{}^{}\mathrm{Pb}$ and ${}_{}{}^{206}{}_{}{}^{}\mathrm{Pb}$. The differential cross sections for excitation of the collective $2^{+}$ and $3^{\mathrm{-}}$ states are well reproduced by model calculations in which it is assumed that ${\mathit{M}}_{\mathit{n}}$/${\mathit{M}}_{\mathit{p}}$=N/Z (i.e., isoscalar character). Angular distributions for the lowest-lying $2^{+}$ states in ${}_{}{}^{203,206}{}_{}{}^{}\mathrm{Pb}$ are significantly different from those for the higher-lying collective $2^{+}$ states, and can be reproduced with ${\mathit{M}}_{\mathit{n}}$/${\mathit{M}}_{\mathit{p}}$≊2.5. The data are compared with random-phase-approximation calculations including pairing, and good agreement is found within estimated uncertainties.

Elastic and inelastic electron scattering has been carried out on ${}_{}{}^{118}{}_{}{}^{}\mathrm{Sn}$ with ${\mathit{q}}_{\mathrm{eff}}$ ranging from 0.40 to 1.15 ${\mathrm{fm}}^{\mathrm{-}1}$. Form factors for the giant isovector dipole and isoscalar quadrupole peaks have been obtained and compared to collective model calculations, with methods closely parallel to those used to treat alpha particle and pion scattering to these same states. The charge responses determined by pion and electron scattering agree within uncertainties for the giant quadrupole peak.

Nuclear structure effects are incorporated in the description of fusion reactions near the Coulomb barrier using the interacting boson model. Predictions of this model are compared with the geometrical model and with sub-barrier fusion and mean angular momentum data for the fusion of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ with the axially symmetric nuclei ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}$ and ${}_{}{}^{166}{}_{}{}^{}\mathrm{Er}$.

Absolute ${\mathrm{\pi }}^{\pm }$d differential cross sections and charge asymmetries have been measured at an incident pion energy of 65 MeV, using an active target of deuterated scintillator plastic to detect recoil deuterons in coincidence with scattered pions. Statistical and systematic uncertainties in the cross sections are each typically ±3%. The charge asymmetry is consistent with theoretical predictions.

An extension of the U(3) limit of the vibron model is proposed to incorporate fermionic degrees of freedom in the algebraic model of nuclear clusterization. This approach enables us to treat explicitly nucleons or holes occupying single-particle states of an oscillator shell in one of the clusters. The dynamical symmetries of the vibron-fermion model built on the U(3) boson dynamical symmetry are explored, and the coupled vibron-fermion bases are constructed. Closed expressions are obtained for the energy spectrum in each case. We suggest that the α-cluster states of the ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$ nucleus may be good examples for the application of the SU(3)×U(2) dynamical symmetry. This phenomenologic algebraic model shows some similarity with the local potential cluster model of Buck et al.

The SU(3)×U(2) limit of the vibron-fermion model introduced recently by us as an algebraic approach to cluster states in odd-mass nuclei is developed further. The electromagnetic transition operators ${\mathit{T}}^{\left(\mathit{E}2\right)}$, ${\mathit{T}}^{\left(\mathit{M}1\right)}$ and ${\mathit{T}}^{\left(\mathit{E}1\right)}$ are constructed, together with the one-nucleon transfer operators. Experimental data available for the α-cluster states of the ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$ nucleus are analyzed in terms of our model to test its applicability. It is found that, although some quantities are not reproduced very well, the overall performance of the model is satisfactory. Furthermore, the phenomenological operators introduced here are able to describe the most intensive transitions in the lowest order; while introducing higher-order (two- or three-body) terms they also qualitatively give account of the less intensive transitions.

We have investigated, in a mean-field approximation, the properties of multi-lambda matter within a highly nonlinear σ-ω obtained from a derivative coupling between the scalar and fermion fields. The matter composition and saturation properties are calculated. We also discuss the spin-orbit properties of the effective Lagrangian.

A time-dependent mean field approximation is applied to a simple bosonic model that is related to the phase transition from spherical to deformed nuclei. It is shown that this approximation is very appropriate for the detection of this phase transition. A method for extracting matrix elements is developed and applied for the two-particle transfer operator in this model.

Average values of matrix elements of the effective nucleon-nucleon interaction can be extracted from measured binding energies and spectra using a variety of simple techniques. Such techniques are applied to data in the mass range A=28–64 to yield information about the interaction energy of nucleons occupying the 2${\mathit{s}}_{1/2}$, 1${\mathit{d}}_{3/2}$, 1${\mathit{f}}_{7/2}$, and 2${\mathit{p}}_{3/2}$ shell-model orbits. The resulting interaction centroids are compared with values provided by other methods, such as shell-model fits to experimental energy levels, calculation of the G matrix from free nucleon-nucleon potentials, and extraction of interaction matrix elements directly from the spectra of nuclei with two nucleons relative to a closed shell. The empirical centroids are shown to be surprisingly accurate.

We determine the parameters of an algebraic radial wave function (a solution of the Ginocchio potential) corresponding to the ${\mathit{d}}_{5/2}$ valence neutron orbital of ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$ by making a fit to the high ${\mathit{q}}^2$ magnetic electron scattering data. The wave function so determined is similar to other finite well wave functions also fitted to these data. It has, however, an rms radius about 6–10 % larger than the corresponding Woods-Saxon wave functions. We suggest from this result that (i) the determination of rms radii of valence nucleon radial wave functions from magnetic electron scattering is more model dependent than previously realized, and (ii) the Okamoto-Nolen-Schiffer anomaly in A=17 may be underestimated by previous calculations with finite wells.

A classical relativistic approach based in the Vlasov equation is applied to the study of infinite nuclear matter. Hadronic matter couples to massive scalar and vector fields. The small-amplitude oscillations around a stationary state are studied. Orthogonality and completeness relations and the energy-weighted sum rule are obtained for the longitudinal modes. The appearance of the zero-sound mode and the distribution of the strength among the different modes are discussed. It is seen that the scalar field only couples to the low-energy excitations at high densities and for wavelengths not too long. The vector field couples strongly to the low-energy excitations. The long-wavelength limit and high-density limit are studied.

All available hindrance factors of alpha transitions to low-lying negative-parity states in doubly even nuclei, to odd-A parity doublets and to doubly odd parity doublet bands, are used to study the systematics of reflection asymmetry in the A∼218–230 region. Special attention is given to the polarization effect of the odd particle in increasing reflection asymmetry and therefore decreasing hindrance factors to the opposite parity states of octupole bands.

The interacting boson approximation model, extended by allowing one boson to break and form a quasiparticle pair, is investigated in the SU(3) limit. Electromagnetic properties of yrast states are studied for the algebraic analogs of both the decoupling and strong-coupling limits. The effects of a pair-breaking interaction that mixes states with different numbers of quasiparticles are investigated for E2 transitions between yrast states. For the algebraic analog of the decoupling limit, it is shown that the mixing interaction has a strong influence on transitions in the region of crossing between the ground-state band and the lowest two-quasiparticle (2qp) band. The mixing interaction does not change the electromagnetic properties of the states of the ground-state band. This effect is due to the approximate cancellation between self-energy and vertex corrections, which corresponds to the nuclear Ward identity. For the algebraic analog of the strong-coupling limit, the K forbiddeness of E2 transitions between the ground-state band and the lowest 2qp band is high, and therefore the influence of the mixing interaction is negligible.

A shell-model study is made of first-forbidden β decay and related processes in A=205–212 nuclei. The interactions used are modifications of the Kuo-Herling realistic effective interactions for particles above and holes below ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ and a cross-shell G-matrix interaction connecting these two. Large-scale diagonalizations are made of 1p-1h excitations across the double-shell closure at ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$. The calculations of the first-forbidden rates use effective single-particle matrix elements which incorporate core polarization of the final state to first order. All first-order initial state 1p-1h admixtures are included explicitly in the diagonalization. A least-squares fit of theory to experiment for eighteen ΔJ=0 and 1 decay rates was made with two unknowns: (1) an enhancement factor ${\mathrm{\epsilon }}_{\mathrm{mec}}$ for the rank zero matrix element of ${\gamma }_5$, and (2) an overall scaling factor for the rank one component of the decay rate. A good fit is achieved yielding ${\mathrm{\epsilon }}_{\mathrm{mec}}$=2.01±0.05 and a rank-one scaling factor of 0.97±0.06. The agreement of the latter with unity indicates a satisfactory understanding of the rank-one component of the decay. The result ${\mathrm{\epsilon }}_{\mathrm{mec}}$=2.01±0.05 indicates an enhancement of the matrix element of ${\gamma }_5$ by 100% over the impulse approximation. A 40% effect is predicted from meson exchange. Thus, a deficiency in the meson-exchange calculation or some further as-yet-unforeseen contribution is suggested. Predictions for twenty other decays in A=205–211 nuclei are compared to experiment and found to be in good general agreement. A calculation of the capture of neutrinos by ${}_{}{}^{205}{}_{}{}^{}\mathrm{Tl}$ is described in detail.

Spectra, angular distributions, and integrated cross sections for inclusive inelastic scattering of 96.5-MeV ${\mathrm{\pi }}^{+}$ and ${\mathrm{\pi }}^{\mathrm{-}}$ from ${}_{}{}^2{}_{}{}^{}\mathrm{H}$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$, and ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ are presented. The measurements were made using a high-pressure gas cell, which permits an accurate determination of relative cross sections for all targets. The data are compared with distorted-wave impulse-approximation calculations and with a modified plane-wave impulse-approximation calculation. In addition, by combining the total inelastic cross sections from this work with estimates of single-charge-exchange cross sections and with published values and reasonable estimates of the other ${\mathrm{\pi }}^{+}$ cross sections at the same energy, values for total reaction and pion absorption cross sections are obtained for all the targets. The dependence of these cross sections on Z, N, nuclear density, and nuclear binding energy is discussed in terms of a simple model.

The ${\mathrm{\beta }}^{\mathrm{-}}$ decay of the ${}_{}{}^{212}{}_{}{}^{}\mathrm{Bi}$ ground state (${\mathit{T}}_{1/2}$=61 min) and the isomers ${}_{}{}^{212}{}_{}{}^{}\mathrm{Bi}_{}^{\mathit{m}1}{}_{}{}^{}$ (${\mathit{T}}_{1/2}$=27 min), and ${}_{}{}^{212}{}_{}{}^{}\mathrm{Bi}_{}^{\mathit{m}2}{}_{}{}^{}$ (${\mathit{T}}_{1/2}$=8 min) are considered in the spherical shell model. The wave functions and energy spectra of all even and odd states in the Kuo-Herling model space were calculated for both ${}_{}{}^{212}{}_{}{}^{}\mathrm{Bi}$ and ${}_{}{}^{212}{}_{}{}^{}\mathrm{Po}$. Possible candidates for the two ${}_{}{}^{212}{}_{}{}^{}\mathrm{Bi}$ isomers were located from these results and the allowed and first-forbidden ${\mathrm{\beta }}^{\mathrm{-}}$ decays rates were formed using a recently developed parametrization of first-forbidden decays in the lead region. It was concluded that ${}_{}{}^{212}{}_{}{}^{}\mathrm{Bi}_{}^{\mathit{m}1}{}_{}{}^{}$ is the yrast $8^{\mathrm{-}}$ state and ${}_{}{}^{212}{}_{}{}^{}\mathrm{Bi}_{}^{\mathit{m}2}{}_{}{}^{}$ the yrast ${18}^{\mathrm{-}}$ state of ${}_{}{}^{212}{}_{}{}^{}\mathrm{Bi}$. The decay rates calculated for these two ${\mathrm{\beta }}^{\mathrm{-}}$ emitters are in excellent agreement with experiment. The predictions for the decay of the ground state of ${}_{}{}^{212}{}_{}{}^{}\mathrm{Bi}$ are not in good agreement with experiment, illustrating the difficulty of calculating weak first-forbidden decay modes reliably.

Shell-model calculations in the model space of the (0d,1s) and (0f,1p) major shells are made for the 1/$2^{+}$ and 3/$2^{+}$ states of ${}_{}{}^{41}{}_{}{}^{}\mathrm{Cl}$, the odd-parity states of ${}_{}{}^{41}{}_{}{}^{}\mathrm{Ar}$, and the even-parity states of ${}_{}{}^{42}{}_{}{}^{}\mathrm{Ar}$. Calculations for ${}_{}{}^{42}{}_{}{}^{}\mathrm{Cl}$, the even-parity states of ${}_{}{}^{41}{}_{}{}^{}\mathrm{Ar}$, and the odd-parity states of ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ar}$ were performed with various degrees of truncation. The results for the ${}_{}{}^{41}{}_{}{}^{}\mathrm{Cl}$ ground state indicate ${\mathit{J}}^{\mathrm{\pi }}$=3/$2^{+}$ with a binding energy of -345 183 keV in excellent agreement with the experimental value of -345 020±150 keV. The predicted binding energies of ${}_{}{}^{41\mathrm{-}43}{}_{}{}^{}\mathrm{Ar}$ are also in good agreement with experiment. The wave functions for the A=41 and 42 nuclei are used to calculate first-forbidden ${\mathrm{\beta }}^{\mathrm{-}}$-decay rates. The 1/$2^{+}$ and 3/$2^{+}$ states of ${}_{}{}^{41}{}_{}{}^{}\mathrm{Ar}$ are considered in a truncated model space and the results are used to estimate the allowed ${\mathrm{\beta }}^{\mathrm{-}}$-decays rates of ${}_{}{}^{41}{}_{}{}^{}\mathrm{Cl}$. Spectroscopic factors and electromagnetic transition rates are calculated for ${}_{}{}^{41}{}_{}{}^{}\mathrm{Ar}$ and compared to experiment. ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ar}$ is predicted to have a 5/$2^{\mathrm{-}}$ ground state.