Doppler-shift attenuation measurements following the inelastic neutron scattering reaction have been employed to determine the lifetimes of a large number of states in ${}_{}{}^{146}{}_{}{}^{}\mathrm{Nd}$, and many fast $E1\mathrm{}$ transitions have been identified. From an examination of this new information and similar data for two $N=82\mathrm{}$ nuclei, ambiguities in determining the degree of nuclear collectivity from reduced $E1\mathrm{}$ transition rates are illustrated.

For central collisions of 1360 MeV ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ + Ag we report correlations in relative momentum and in velocity difference for ${}_{}{}^{1,2,3}{}_{}{}^{}\mathrm{H}$ ejectiles at 32° and 68°. Comparison to trajectory calculations gives a measure of the mean emission times, and, for unlike pairs, the average emission orders. There is a strong variation of the average emission times as a function of ejectile energy that is very similar for each H isotope; they change from ≳1000 fm/c for ∼10 MeV in the c.m. to ≲50 fm/c for ≳30 MeV. This indicates a broad spectrum of emission sources and associated characteristics. The longer times suggest evaporative emission from thermalized systems for ${}_{}{}^{1,2,3}{}_{}{}^{}\mathrm{H}$ of energies ∼10 MeV (i.e., those near the emission barrier). The shorter times, along with the observed energy spectra, suggest extensive prethermalization or direct emission from the central collision zone for ${}_{}{}^{1,2,3}{}_{}{}^{}\mathrm{H}$ ejectiles of much higher energy.

The nucleus ${}_{}{}^{114}{}_{}{}^{}\mathrm{Te}$ has been studied in heavy-ion γ-ray spectroscopy experiments performed with the early implementation of the GAMMASPHERE multidetector array. Three rotational intruder bands have been observed up to high spins. The yrast band, involving the 4p2h (${\mathit{h}}_{11/2}$${)}^2$(${\mathit{g}}_{7/2}$${)}^2$(${\mathit{g}}_{9/2}$${)}^{\mathrm{-}2}$ proton configuration, reaches I=48ħ at an excitation energy of 30.3 MeV, the highest observed spin connected by γ rays in this mass region. The band properties are interpreted in the framework of smooth band termination.

We propose a theoretical description of superdeformed bands based on the projected shell model. The shell model basis is constructed at the superdeformed minimum and projected onto states of good angular momentum, and a two-body Hamiltonian is then diagonalized in this basis. We take the superdeformed band in ${}_{}{}^{132}{}_{}{}^{}\mathrm{Ce}$ as an example. Good agreement with the measured gamma-ray energies allows us to suggest spin values for these superdeformed states. Finally, we propose an explanation for the recently observed ΔI=4 bifurcation disappearance at a rotational frequency of ħω≃0.65 in this nucleus.

We show that the very strong Coulomb dipole polarizability and breakup of ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ reduces significantly its near-barrier fusion cross section with a heavy target nucleus. We suggest that the measurement of ${\mathrm{\sigma }}_{\mathit{F}}$ concomitantly with that of the elastic scattering would allow an unambiguous extraction of the dipole polarizability of halo nuclei.

The spin-dependent total cross-section difference Δ${\mathrm{\sigma }}_{\mathit{T}}$ has been measured at energies of 7.43, 9.57, and 11.60 MeV for neutrons, polarized transverse to the beam momentum, transmitted through a transversely polarized proton target. In addition, the energy at which Δ${\mathrm{\sigma }}_{\mathit{T}}$ crosses through zero has been determined in the energy range 3.65–6.25 MeV. The measurements were carried out with a polarized ${\mathrm{TiH}}_2$ target and polarized neutrons from the ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(p,n${)}^3$He and ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(d,n${)}^3$He reactions. The cross-section differences Δ${\mathrm{\sigma }}_{\mathit{T}}$ are sensitive to the strength of the ${}_{}{}^3{}_{}{}^{}$${\mathit{S}}_1$${–}^3$${\mathit{D}}_1$ mixing parameter ${\mathrm{\epsilon }}_1$. Phase-shift analyses are used to determine ${\mathrm{\epsilon }}_1$ values from the data. The values are in good in agreement with NN potential models and do not support the low ${\mathrm{\epsilon }}_1$ values found in previous studies around 15–20 MeV.

A detailed comparison of Faddeev and variational wave functions for ${}_{}{}^3{}_{}{}^{}\mathrm{H}$, calculated with realistic nuclear forces, has been made to study the form of three-body correlations in few-body nuclei. Three new three-body correlations for use in variational wave functions have been identified, which substantially reduce the difference with the Faddeev wave function. The difference between the variational upper bound and the Faddeev binding energy is reduced by half, to typically <2%. These three-body correlations also produce a significant lowering of the variational binding energy for ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ and larger nuclei.

We study two pion correlations from Skyrmion and anti-Skyrmion collision, using the product ansatz and an approximate random grooming method for nucleon projection. The spatial-isospin coupling inherent in the Skyrme model, along with empirical averages, leads to correlations not only among pions of like charges but also among unlike charge types.

We investigate the effect of meson-decay diagrams on the proton-proton bremsstrahlung process. We explicitly include short-range correlations by calculating single- and double-scattering diagrams using an NN T-matrix interaction. We find that in general these diagrams interfere destructively with the corresponding Born amplitudes so that the net effect of the meson-decay process on proton-proton bremsstrahlung reactions is considerably smaller than that of the Born amplitude alone.

The inelastic neutron scattering reaction has been used to populate known $1^{+}$ scissors mode states in the deformed rare-earth nuclei ${}_{}{}^{162}{}_{}{}^{}\mathrm{Dy}$ and ${}_{}{}^{164}{}_{}{}^{}\mathrm{Dy}$. The electromagnetic decay properties of these states have been examined and the Doppler-shift attenuation method has been used to measure directly the lifetimes of these states. The $M1\mathrm{}$ strengths determined are in general agreement with those measured previously in nuclear resonance fluorescence experiments and support the conclusion that these are collective structures; however, a significant discrepancy is found for three states near 3.1 MeV in ${}_{}{}^{164}{}_{}{}^{}\mathrm{Dy}$. Candidates for $2^{+}$ rotational band members have been identified, and a previously suggested $\gamma$-ray branch from a spin-1 state to the $\gamma$ vibration in ${}_{}{}^{164}{}_{}{}^{}\mathrm{Dy}$ has been observed.

The excited levels of ${}_{}{}^{142}{}_{}{}^{}\mathrm{Ce}$ have been studied using the (n,${\mathit{n}}^{\prime }$γ) reaction. Excitation functions, angular distributions, and Doppler shifts were measured for γ rays from levels up to an excitation energy of 3.3 MeV; multipole-mixing and branching ratios and transition rates were deduced. Theoretical predictions of electromagnetic transition rates were compared for the interacting boson model, the quasiparticle phonon model, and the particle-core coupling model with experimental values. Evidence is found supporting the fragmentation of mixed-symmetry strength among neighboring ${}_{}{}^{142}{}_{}{}^{}\mathrm{Ce}$ excited levels. This fragmentation is evinced in the $2^{+}$ excitations through strong M1 transitions; however, the $3^{+}$ mixed-symmetry strength is not manifested directly through strong M1 transitions, but rather is implied through model calculations. Candidates for multiphonon excitations are identified for the three-quadrupole and quadrupole-octupole phonon quintets.

The (α${,}^3$He-n) reaction has been investigated at 120 MeV incident energy on ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}$, ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$, and ${}_{}{}^{120}{}_{}{}^{}\mathrm{Sn}$ target nuclei. Neutrons in coincidence with ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ particles emitted at 0° were detected using the multidetector array EDEN, in order to get information about the decay of single-particle states embedded in the (α${,}^3$He) continuum. Neutron angular correlations, multiplicity values, and branching ratios to low-lying states of the final nuclei have been compared with the predictions of the statistical decay model. Evidence for a significant nonstatistical decay branch has been observed in the three nuclei below about 15 MeV excitation energy. Direct branching ratios in ${}_{}{}^{91}{}_{}{}^{}\mathrm{Zr}$ deduced from this analysis are compared with the predictions of two nuclear structure models. At higher excitation energy, the decay characteristics of the (α${,}^3$He) continuum are shown to be mainly statistical.

High-spin states were populated in ${}_{}{}^{172}{}_{}{}^{}\mathrm{Hf}$ with the ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$${+}^{128}$Te reaction at 200 and 214 MeV. All of the known rotational bands in ${}_{}{}^{172}{}_{}{}^{}\mathrm{Hf}$ have been extended and five new rotational bands have been observed using the Gammasphere spectrometer. This study establishes the highest known state in ${}_{}{}^{172}{}_{}{}^{}\mathrm{Hf}$ at spin 44ħ. One of the new bands is a ${\mathit{K}}^{\mathrm{\pi }}$=(${14}^{+}$) strongly coupled rotational band. In conflict with the K-selection rule another newly established bandhead state, with spin I=K=12, is observed to γ decay directly to the yrast ${12}^{+}$ state. This large breakdown in the K-selection rule (ΔK≊12) may be due to a mixing between the low- and high-K states in ${}_{}{}^{172}{}_{}{}^{}\mathrm{Hf}$.

Photon scattering experiments on the odd, deformed nuclei ${}_{}{}^{161,163}{}_{}{}^{}\mathrm{Dy}$ and ${}_{}{}^{157}{}_{}{}^{}\mathrm{Gd}$ provided detailed information on the excitation energies and transition probabilities of low-lying dipole excitations. In the case of the even-even nuclei ${}_{}{}^{162,164}{}_{}{}^{}\mathrm{Dy}$ in addition spins and parities of the excited states could be determined model independently by measuring the angular distributions and the linear polarization of the scattered photons using a Compton polarimeter. The results are compared with the systematics obtained for the neighboring even-even isotopes ${}_{}{}^{160}{}_{}{}^{}\mathrm{Dy}$ and ${}_{}{}^{156,158,160}{}_{}{}^{}\mathrm{Gd}$ in previous photon scattering experiments. Whereas in the odd Dy isotopes a concentration of dipole strength is observed, which fits nicely into the systematics of the orbital M1 mode, the dipole strength in ${}_{}{}^{157}{}_{}{}^{}\mathrm{Gd}$ is completely fragmented into about 90 transitions.

The lifetime τ of the $0_2^{+}$ state in ${}_{}{}^{78}{}_{}{}^{}\mathrm{Kr}$ has been measured by means of the Doppler shift attenuation method in gases. From the value of τ and the measured value of the K-internal conversion branching ${\mathit{I}}_{\mathit{K}}$($0_2^{+}$→$0_1^{+}$)/${\mathit{I}}_{\mathit{K}}$($0_2^{+}$→$2_1^{+}$) the value of the electric monopole strength ${\mathrm{\rho }}^2$(E0) of the $0_2^{+}$→$0_1^{+}$ transition has been deduced. Restriction or assignments for the spin parity of several levels in ${}_{}{}^{78}{}_{}{}^{}\mathrm{Kr}$, populated in the decay of ${}_{}{}^{78}{}_{}{}^{}\mathrm{Rb}$, have been deduced by measuring K-internal conversion coefficients of the relevant transitions.

The isotope ${}_{}{}^{105}{}_{}{}^{}\mathrm{Ag}$ has been studied using 169.5 MeV ${}_{}{}^{37}{}_{}{}^{}\mathrm{Cl}$ ions impinging on ${}_{}{}^{76}{}_{}{}^{}\mathrm{Ge}$. The Nordball Ge array detected the γ rays and a 4π charged particle detector system detected emitted light charged particles. A very deformed band has been established using Doppler shift attenuation methods. The analysis is based on the γγ coincidences and the angular dependence of the four rings of Ge detectors in Nordball. The deformation of the band is deduced to be ${\mathrm{\beta }}_2$=0.${37}_{\mathrm{-}0.02}^{+0.03\mathrm{}}$.

Isospin-mixing corrections for superallowed Fermi transitions in fp-shell nuclei are computed within the framework of the shell model. The study includes three nuclei that are part of the set of nine accurately measured transitions as well as five cases that are expected to be measured in the future at radioactive-beam facilities. We also include some new calculations for ${}_{}{}^{10}{}_{}{}^{}\mathrm{C}$. With the isospin-mixing corrections applied to the nine accurately measured ft values, the conserved-vector-current hypothesis and the unitarity condition of the Cabbibo-Kobayashi-Maskawa matrix are tested.

States in the ${}_{}{}^{11}{}_{}{}^{}\mathrm{Be}$ spectrum, termed halo analog (HA) states, with halo isospin ${\mathit{T}}^{\mathit{h}}$=1, 0 are studied in the framework of a three-body ${(}^9$Li+n+p) approach and a microscopic hyperspherical harmonics method. Three-body bound and scattering (HA) states, with structure similar to the two-neutron halo state of ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$, are obtained in ${}_{}{}^{11}{}_{}{}^{}\mathrm{Be}$ at the excitation energies above 18 MeV and compared with experimental spectra. The influence of the ‘‘deuteronlike’’ halo analog state with T=3/2 (${\mathit{T}}^{\mathit{h}}$=0) on β-delayed deuteron emission from ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ is studied. It is found that the shape of the deuteron spectrum and branching ratio to the ${}_{}{}^9{}_{}{}^{}\mathrm{Li}$+d channel are sensitive to the position of this halo analog state in ${}_{}{}^{11}{}_{}{}^{}\mathrm{Be}$.

Using a quasiparticle Tamm-Dancoff approximation (TDA) based on deformed Hartree-Fock (HF) calculations with Skyrme interactions, the distribution of the Gamow-Teller (GT) ${\mathrm{\beta }}^{+}$ decay strength is estimated for the HF local minima of even-even deformed nuclei near the proton drip line in the region of 28<Z<66. The distribution often depends sensitively on the nuclear shape (namely, oblate or prolate). In the region of Z<50 the possibility of observing β-delayed proton emission depends sensitively on the excess of Z over Z=N. In the region of Z≳50 almost the entire estimated GT strength is found to lie below the ground states of the even-even mother nuclei, and the observation of the total GT strength by β-delayed charged-particle(s) emission will be of essential importance.

We study the motion of classical particles confined in a two-dimensional ‘‘nuclear’’ billiard whose walls undergo periodic shape oscillations according to a fixed multipolarity. The presence of a coupling term in the single-particle Hamiltonian between the particle motion and the collective coordinate generates a fully self-consistent dynamics. We consider in particular monopole oscillations and demonstrate that self-consistency is essential in order to induce chaotic single-particle motion. We also discuss the dissipative behavior of the wall motion and its relation with the order-to-chaos transition in the dynamics of the microscopic degrees of freedom. Analogous considerations can be extended to higher multipolarities.