The signs of the quadrupole moments and the induced nuclear polarization of $8^{+}$ isomers in ${}_{}{}^{88}{}_{}{}^{}$,90Zr have been measured by the tilted multifoil technique. The isomers were populated by pulsed ${}_{}{}^{16}{}_{}{}^{}$,18O beams and polarized by the tilted multifoil interaction. The recoil nuclei were implanted into a single crystal of Zr and the quadrupole precession was observed. The sign of the Q moments was measured to be positive for ${}_{}{}^{88}{}_{}{}^{}\mathrm{Zr}$ and negative for ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$, in accordance with shell model predictions.

A special arrangement of electron spectrometers has been used to search for a weak E5γ transition in ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$. The experiment establishes the upper limit: B(E5,$5_1^{\mathrm{-}}$→$0_2^{+}$)/B(E 5,$5_1^{\mathrm{-}}$→$0_1^{+}$)≤1.8 (90% confidence limit).

A direct evidence of 2ħ-high single particle component has been obtained for the first time in sd-shell nuclei from measurement of ${\alpha }_0$ and ${\mathrm{p}}_0$ decay from the 12.80 MeV state in ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ populated through the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{20}$Ne,α${)}^{28}$Si reaction. This state is assigned $J^{\pi }$${=6\mathrm{}}^{+}$ and has a $g_{9/2}$ single particle component of 20–30 % in a nearly stretched proton configuration of ($g_{9/2}$$d_{5/2}^{\mathrm{-}1}$).

A coupled channels analysis of data from previous work on proton scattering from ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ at 0.8 and 1.0 GeV is presented. Calculations were performed in which the $0^{+}$,$2^{+}$, and $4^{+}$ states were assumed to belong to the ground state rotational band. A deformed Woods-Saxon optical potential, with and without spin-orbit terms, was adjusted to fit the data. The multipole moments of the deformed optical potentials are related to those of the matter distributions by Satchler’s theorem. Although the various values of the moments obtained here from the (p,p’) data agree in sign and are approximately the same in magnitude, the values are consistently smaller for ME(2) and ME(4) than those obtained from (e,e’) and from Hartree-Fock calculations.

We consider a model of nucleon-nucleon interactions in which the nucleon is a Skyrme soliton stabilized by ω-meson exchange, rather than the usual quartic Lagrangian term. Making the product approximation for the meson field matrix U and an additive approximation for the ω field, we obtain nonzero, central, spin-spin, and tensor NN potentials. Their magnitudes, but not shapes, are sensitive to the ω coupling constant. In general, the results are similar to others obtained, using the same kinds of approximations, with the usual Skyrme Lagrangian. Neither approach finds intermediate-range attraction in the I=0 central potential.

An extreme situation is envisaged in which the coupling among the inelastic channels is assumed to be the same as that between the elastic and the inelastic ones. The coupling potentials are surface peaked, of zero multipolarity and of the same sign. A set of six such coupled equations is solved for various strengths of the coupling potentials, in a simulation of 60 MeV neutron scattering from a nucleus like Fe or Ni. The effect of the coupling between the inelastic channels on the elastic phase shifts represents a nuclear polarization correction, and is of third or higher order in the coupling potential. For a strength of the inelastic interchannel coupling potential which is physically reasonable in this schematic model, in that it gives rise to the experimental inelastic cross section, the third order effects are found to be of the order of 80%, i.e., non-negligible. Even though this schematic calculation overemphasizes the role of interchannel coupling, it suggests nevertheless that calculations of nuclear polarization effects in realistic microscopic models should be carried out to an order higher than the second before they can be accepted as being reliable.

We report measurements for in-plane and out-of-plane correlations for p,d,t${,}^3$He, and ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ from 40 MeV/nucleon C+C. Silicon-NaI light particle telescopes were placed at (theta,φ)=(45°,90°) and (45°,180°) and another telescope was moved from theta=25° to 120° at φ=0°. No peak was observed in the ratio of in- to out-of-plane proton-proton correlations at energies corresponding to quasi-elastic scattering. The angular distributions of the ratio of in- to out-of-plane for p-p, d-d, t-t, ${}_{}{}^3{}_{}{}^{}\mathrm{-}_{}^3{}_{}{}^{}$He, and ${}_{}{}^4{}_{}{}^{}\mathrm{-}_{}^4{}_{}{}^{}$He peak around 35° and the maximum value increases monotonically with mass of the particles reaching a value near 4 for ${}_{}{}^4{}_{}{}^{}\mathrm{-}_{}^4{}_{}{}^{}$He. A calculation incorporating simple kinematic effects cannot reproduce the observed correlations for any of the paritcle pairs.

In-beam γ-ray spectroscopy in concert with both massive transfer and fusion reactions has been used to study high-spin states in the relatively neutron-rich ${}_{}{}^{102}{}_{}{}^{}\mathrm{Ru}$ and adjacent mass 100 transitional nuclei. Backbending in ${}_{}{}^{102}{}_{}{}^{}\mathrm{Ru}$ is shown to result from the alignment of a pair of $h_{11/2}$ neutrons. Blocking arguments and cranked shell model calculations support this. Alignment of a pair of $h_{11/2}$ neutrons in the $g_{9/2}$ proton band of ${}_{}{}^{103}{}_{}{}^{}\mathrm{Rh}$ changes the signature splitting and B(M1)/B(E2) ratios.

We report radiochemically determined cross sections for the heaviest known actinides produced in transfer reactions of ${}_{}{}^{16}{}_{}{}^{}$,18O and ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}$ with ${}_{}{}^{254}{}_{}{}^{}\mathrm{Es}$ as a target. A comparison with data for similar transfers from ${}_{}{}^{248}{}_{}{}^{}\mathrm{Cm}$ targets is made. Transfer cross sections are extrapolated for the production of the unknown, neutron-rich isotopes of elements 101 through 105, and the unique potential of ${}_{}{}^{254}{}_{}{}^{}\mathrm{Es}$ as a target to make these exotic nuclei accessible is demonstrated.

We consider the deep inelastic lepton-nuclear scattering taking into account the binding of nucleons and two body correlations. It is shown that the experimental data in the x>1 region are well reproduced when two-body short-range correlations are taken into account.

The energy spectrum of the ${}_{}{}^{12}{}_{}{}^{}$C${+\mathrm{}}^{12}$C resonances is described with the interacting boson (quadrupole) model. The Hamiltonians corresponding to the three dynamical symmetries and to the general case of the model are used. The results are compared with the similar calculations within the nuclear vibron (dipole) model. Based on the present experimental data no choice can be made between the dipole and quadrupole descriptions, but in both cases the best fit is quite close to the dynamical symmetry corresponding to a soft vibrator.

Proton-proton and proton-neutron angular correlations as well as proton and deuteron inclusive spectra from pion absorption on C, Al, Cu, and Ta were measured at $T_{\pi }$=65 MeV. We compared the results with the prediction of the intranuclear cascade model, assuming that pion absorption proceeds only through two-nucleon absorption processes. The differential cross sections of the (${\pi }^{+}$,p) and (${\pi }^{+}$,pp) reactions were fairly well reproduced by the calculation in a wide angular range. Ratios R of the pion absorption cross section on a pn pair to that on a pp or nn pair, were in agreement between the inclusive and exclusive measurements for C and Al, but for Cu, the inclusive measurement gave a smaller R value. The internuclear cascade calculations for the (${\pi }^{\pm }$,pn) and (${\pi }^{\mathrm{-}}$,pp) reactions revealed the importance of the pion charge exchange process before absorption, even at $T_{\pi }$=65 MeV.

The cross section for the absorption of a virtual longitudinal photon in inclusive inelastic electron scattering from nuclei is governed by the quark (charge) density-density correlation function. In this work we assume that quarks are localized in nucleons and show that we can then describe the longitudinal response in terms of nucleon degrees of freedom. Our calculations make use of medium-modified nucleon form factors we have introduced previously. We discuss the Coulomb sum rule and present results of calculations of the integrated longitudinal response made using a relativistic Fermi-gas model of the nucleus. We predict that the integrated response is quenched by about 30 percent at ‖q‖=410 MeV and about 45 percent at ‖q‖=550 MeV for ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$. Our predictions appear to be in accord with the data for the integrated response function and support our prediction of increased nucleon size in nuclei.

Angular distributions and angle integrated cross sections are calculated in the distorted-wave Born approximation framework for the ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$(p,${\Delta }^{++}$${)}^6$He reaction at several energies between 400 and 1250 MeV. The optical potentials for Δ at these energies are estimated using the available nucleon-nucleon elastic scattering data, pp→NΔ data, and the reciprocity theorem. The NN→NΔ interaction is described by the one-pion- and one-rho-exchange interaction.

Electric monopole (E0) transitions between low lying levels in ${}_{}{}^{102}{}_{}{}^{}\mathrm{Ru}$, populated in the decay of ${}_{}{}^{102}{}_{}{}^{}\mathrm{Rh}$, have been investigated by means of conversion-electron and γ-ray spectroscopy. Values or upper limits for the ratio X(E0/E2) of E0 to E2 reduced transition probabilities have been derived for the transitions from the $0_3^{+}$ and $0_2^{+}$ to the $0_1^{+}$ and $2_1^{+}$ states and for the $2_2^{+}$→$2_1^{+}$ transition. The experimental results are discussed in the frame of a schematic interacting boson model.

The g factors of the $2_1^{+}$ states in ${}_{}{}^{146}{}_{}{}^{}$,148Ce have been measured using the time integral perturbed angular correlation technique. The levels were populated by the radioactive decay of mass-separated ${}_{}{}^{146}{}_{}{}^{}$,148La which was produced by thermal neutron fission of ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$. The measured g${(2\mathrm{}}_1^{+}$) values are 0.24±0.05 and 0.37±0.06 for ${}_{}{}^{146}{}_{}{}^{}\mathrm{Ce}$ and ${}_{}{}^{148}{}_{}{}^{}\mathrm{Ce}$, respectively. The results are interpreted as a probe of the number of valence protons participating in the collective motion. Data for Ba, Ce, Nd, and Sm nuclei in the region of N=90 show a distinct change in the value of g${(2\mathrm{}}_1^{+}$) as the number of neutrons increases from 86 to 90. This change is attributed to the effects of the strong interaction between the π$h_{11/2}$ and ν$h_{9/2}$ orbits which causes a gradual dissipation of the Z=64 subshell gap.

The decay of ${}_{}{}^{148}{}_{}{}^{}\mathrm{Pr}$ to levels of ${}_{}{}^{148}{}_{}{}^{}\mathrm{Nd}$ has been studied using sources produced by the ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$(n,f) reaction followed by on-line mass separation, and by the ${}_{}{}^{148}{}_{}{}^{}\mathrm{Nd}$(n,p) reaction using an enriched ${}_{}{}^{148}{}_{}{}^{}\mathrm{Nd}$ target. Strong evidence is presented to support the previously proposed existence of a 2.27±0.05 min low-spin ${(1\mathrm{}}^{\mathrm{-}}$) isomer and a 1.95±0.08 min high-spin ${(4\mathrm{}}^{\mathrm{-}}$) isomer in ${}_{}{}^{148}{}_{}{}^{}\mathrm{Pr}$. The presence of levels at ${301.7(2}^{+}$), ${752.3(4}^{+}$), ${916.9(0}^{+}$), ${999.3(3}^{\mathrm{-}}$), ${1023.0(1}^{\mathrm{-}}$), ${1171.0(2}^{+}$), ${1241.6(5}^{\mathrm{-}}$), ${1248.7(2}^{+}$), and ${1279.7(6}^{+}$) keV in ${}_{}{}^{148}{}_{}{}^{}\mathrm{Nd}$ is also supported.

It is shown that it is not necessary to resort to an explicit mapping of the fermion basis into the boson space when bifermion excitations are treated in a boson picture. One may use the usual ideal boson basis in the boson space. Under certain circumstances this may lead to the occurrence of spurious states. However, these do not mix with the physical states and they can be identified by means of a simple procedure which is developed within the framework of the Dyson boson method. The results are illustrated by means of three interesting cases in the Sp(4) model.

It is shown that in both the nuclear shell model, considering explicitly proton and neutron degrees of freedom (seniority scheme), and in particle-core coupling model calculations, $2^{+}$ levels with symmetric and antisymmetric character in the constituent unperturbed basis result. Besides the excitation energy for such $2^{+}$ levels, the E2 decay properties also are studied. Constructive and destructive interference between the two distinct E2 matrix elements results for the $2_1^{+}$ (symmetric) and $2_2^{+}$ (antisymmetric) levels, respectively. Applications are shown for the Cd (Z=48) and the N=84 nuclei.