In view of the current experimental interest in utilizing ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(p,p’γ${)}^{12}$C spin observables to supplement the data on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(p,p’${)}^{12}$${\mathrm{C}}^{\mathrm{*}}$($1^{+}$), we study the inelastic scattering from the point of view of the Goldstein-Moravcsik theorem, and identify 32 additional possible sets of (p,p’γ) measurements. Compared to sets containing 16 observables [including eight on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(p,p’${)}^{12}$${\mathrm{C}}^{\mathrm{*}}$], we find four different sets, each of which contain only a total of 14 observables and eighteen sets which contain only 15. Each set can lead to the unambiguous determination of the six inelastic amplitudes.

Differential elastic and inelastic scattering cross sections have been measured for neutrons incident on ${}_{}{}^{204}{}_{}{}^{}\mathrm{Pb}$ and ${}_{}{}^{206}{}_{}{}^{}\mathrm{Pb}$ at energies of 2.5, 4.6, and 8.0 MeV and total cross sections in 100-keV steps from 250 keV to 4.0 MeV. Both spherical and coupled-channels analyses have been used to interpret this large set of data, together with other cross sections extending to 8 MeV. Several purposes motivate this work. The first is to establish the dispersion-corrected mean field appropriate for these nuclei. A consistent description of the energy dependent neutron scattering potential includes a dispersion relation connecting the real and imaginary parts of the potential; the resultant potential relates the energy dependent scattering field to one representing bound single particle levels. Dispersion relations using both the single channel and coupled-channels models have been examined; both give very similar results. The second motivation is to deduce neutron and proton excitation strengths of the lowest-energy quadrupole and octupole excitations seen via neutron scattering, and to compare those strengths with similar values derived from electromagnetic exciton, heavy-ion and pion scattering. The role of target neutrons in both collective excitations was found to be enhanced compared to the proton role.

The high spin levels of ${}_{}{}^{84}{}_{}{}^{}\mathrm{Y}$ have been established up to 12 MeV excitation energy and probable spin of ${25}^{+}$ through the reaction ${}_{}{}^{59}{}_{}{}^{}\mathrm{Co}$${(}^{28}$Si,2pn${)}^{84}$Y using in-beam γ-ray spectroscopic techniques. The γ transitions in ${}_{}{}^{84}{}_{}{}^{}\mathrm{Y}$ have been identified through the particle-gamma coincidences. The level scheme was constructed through the γ-γ coincidences, angular distribution, and directional correlation orientation ratios. The positive parity yrast band built on the (π${\mathit{g}}_{9/2}$⊗ν${\mathit{g}}_{9/2}$) configuration shows a large signature splitting and a signature inversion at I∼11ħ. The measured B(E2; I→I-2) values give a deformation ${\mathrm{\beta }}_2$∼0.17. The negative parity band shows a signature inversion at I∼11ħ and B(M1; I→I-1) enhancement for I>11ħ. The projected Hartree-Fock and the cranked shell model calculations provide an understanding for the observed properties of the energy levels in ${}_{}{}^{84}{}_{}{}^{}\mathrm{Y}$.

Analogies and differences between the random phase approximation (RPA) and the Gaussian approximation at finite temperature are discussed. A comparison is made for Hartree and Hartree-Fock temperature dependent mean fields. Some ambiguities, in the definition of the Hartree mean field and in the relative correction, are analyzed. In a solvable model with a repulsive potential, the Gaussian approximation and the RPA, both built from the Hartree mean field, are found more reliable than the RPA built from a Hartree-Fock mean field.

A conceptually different interpretation of the excitation energies and signature inversion in negative parity bands of odd-Z and odd-N nuclei has been given within the framework of triaxial rotor plus one quasiparticle model. Furthermore, in the present work, evidence has been obtained for a triaxial shape transition in these nuclei related to a sudden decrease in the signature splitting.

The energy spectra, α-spectroscopic factors, and E2 transitions of ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ are studied by the α${+}^{36}$Ar orthogonality condition model. The calculated properties are in good overall agreement with the experimental data. Both of the K=$0^{+}$ and $0^{\mathrm{-}}$ cluster bands are successfully reproduced by the model. It is found that the coexistence and interference of α-cluster states and shell-model states are important for understanding the structure of ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$.

A detailed study of sum rules for E0,${\mathit{E}}_2$ and M1 and M3 transitions within the framework of the proton-neutron interacting boson model (IBM-2) is carried out. Both the non-energy-weighted as well as linear energy-weighted sum rules are derived for rather general IBM-2 Hamiltonians. Special attention is given to the M1 sum rule for which a large amount of data exists. We also show how these more general sum rule results reduce to simple answers when considering the limit of U(5), SU(3), and O(6) dynamical symmetries. Finally, a relation between the M1 and M3 sum rules is pointed out.

The triton binding energy, and the partly real and partly complex neutron-deuteron doublet channel elastic scattering phase shifts, calculated by means of the exact three-body theory, are used as input in the fixed-l inverse scattering theory of Marchenko. The local potentials obtained hereby are independent of energy, and complex. Their strong imaginary part reflects the strong absorption in the doublet channel arising from the opening of the deuteron breakup channel. For total orbital angular momentum l different from zero the potentials are unique, reproducing the input phase shift in the whole energy region. For l=0 where there exists, in addition, a bound state we construct a one-parameter class of complex local potentials which are phase–binding-energy equivalent; that is, each of its members reproduces, in addition to the partly complex phase shifts, the bound state with the physical, i.e., real binding energy. Correlations between the oscilliations in the radial independence of these equivalent potentials and physical properties of the input data are established.

The Gogny force is used to study, in the framework of the mean field theory and the collective Hamiltonian method, the octupole correlations present in the ${}_{}{}^{138–148}{}_{}{}^{}\mathrm{Xe}$ nuclei. The energy splittings between the ground state and the lowest-lying negative parity state are computed as well as the B(E1) and B(E3) transition probabilities. A peculiar behavior of the B(E1)’s as a function of neutron number is predicted.

The thermal and the time-dependent versions of the Hartree-Fock-Bogoliubov approximation are used to describe the effects of the pairing interaction in a simple model. Similarities and differences between the two approaches are discussed. In the one-shell case analytic results are obtained which clearly show that as the degeneracy increases the exact energies tend to the limits provided by the approximate methods. A relation between the quasiparticle occupation probability and the seniority is established. In the two-shell case the time-dependent approach approximates all the families of exact states labeled by the shell seniority and gives information on the two different phase transitions present in the model. The finite-temperature method, instead, only approximates the exact energy for the lowest state of each family.

Three-body bound systems are investigated in the limit of very weak binding by use of hyperspherical harmonics. The short-range two-body potentials are assumed to be unable to bind the binary subsystems. Then the mean square radius always converges for vanishing binding except for the most spherical wave function, where all angular momenta involved are zero, which diverges logarithmically. Universal scaling properties are suggested. Any additional long-range repulsive potential, like, for example, the Coulomb potential, leads to finite radial moments even for vanishing binding. Spatially extended charged halos are only possible for very low charges. The spatial extension of three-body systems is in the asymptotic region more confined than for corresponding two-body systems, where the divergences are stronger and more abundant. Numerical examples and transitions to the asymptotic region are shown for square well and Gaussian two-body potentials. The results are applied to several drip-line nuclei.

Within a quasipotential framework a relativistic analysis is presented of the deuteron current. Assuming that the singularities from the nucleon propagators are important, a so-called equal time approximation of the current is constructed. This is applied to both elastic and inelastic electron scattering. As dynamical model the relativistic one boson exchange model is used. Reasonable agreement is found with a previous relativistic calculation of the elastic electromagnetic form factors of the deuteron. For the unpolarized inelastic electron scattering effects of final-state interactions and relativistic corrections to the structure functions are considered in the impulse approximation. Two specific kinematic situations are studied as examples.

The method of Liu and Zamick for the exclusion of spurious M1 strength through effective operators is extended to isoscalar and isovector operators and applied to heavy deformed nuclei using a Woods-Saxon potential pairing. The isoscalar orbital strength is almost purely spurious and carries most of the total amount of spuriousity. The method gives the exact summed nonspurious strength, but becomes approximate when applied to single $1^{+}$ excitations. The accuracy of this approximation is studied here by comparison with exact, rotationally invariant random-phase-approximation results. It is shown that for some residual interactions the ‘‘approximate’’ results can be very different from the exact ones even in the presence of relatively small changes in the B(M1) values or close to the exact results even for large changes. Exact results are at present the only reliable test for the validity of approximate methods for the removal of spuriousity.

Previously proposed high spin states in ${}_{}{}^{22,23}{}_{}{}^{}\mathrm{Na}$ are compared with calculations from the cranked Nilsson model including Strutinsky renormalization. High K rotational isomers are proposed for ${\mathit{I}}^{\mathrm{\pi }}$=$6^{\mathrm{-}}$ in ${}_{}{}^{22}{}_{}{}^{}\mathrm{Na}$ and 11/$2^{+}$, 13/$2^{+}$, and possibly 15/$2^{+}$ in ${}_{}{}^{23}{}_{}{}^{}\mathrm{Na}$. The positive parity yrast sequences in these two nuclei are analyzed in terms of the change from collective to single particle behavior at I=9 ${(}^{22}$Na) and 17/2 ${(}^{23}$Na). The systematics of band terminations in eight nuclei between ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ and ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$ shows that ${\mathit{I}}^{\max }$ or ${\mathit{I}}^{\max }$-1 has tentatively been reached in six of these eight nuclei, where ${\mathit{I}}^{\max }$ is the maximum possible sd shell spin for the given nucleus.

In this paper we develop various parametrizations of the nuclear matter Dirac-Brueckner G matrix, which are suitable for application in relativistic Hartree-Fock calculations of finite nuclei. The relativistic one boson exchange model forms the basis of this effective interaction. The parameters, which are obtained from a least squares fit, explicitly depend on the density. We also require the interaction to reproduce the self-energies and the binding energy of nuclear matter very accurately. It is shown that for densities up to 1.5 times normal nuclear density the saturation curve virtually coincides with the original Dirac-Brueckner result and yields a good prediction of the nuclear matter compressibility.

Fusion-evaporation cross sections for the ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$${+}^{154}$Sm system at bombarding energies near the Coulomb barrier have been measured by off-line observation of the K x rays emitted in the radioactive decay of the residual nuclei. The total fusion cross sections were obtained by adding the contributions from evaporation and fission processes. The fusion excitation function for this system is compared with coupled-channel calculations that include the deformation of the target and vibrational states of both target and projectile.

The spectral distributions of δ electrons emitted in dissipative heavy-ion collisions represent an established tool to study the time evolution of the collision process. Especially, the yield of high-energy δ electrons, which are measured for the first time up to an energy of 8 MeV, reflects short time scales and offers a unique possibility to examine the short deceleration phase at the beginning of the collision, which takes place within a few ${10}^{\mathrm{-}22}$ s. The δ-electron spectra measured in dissipative collisions of Pb+Pb at an incident energy of 12 MeV/nucleon are compared with theoretical predictions using a coupled-channels formalism. The nuclear trajectories needed as input for the calculations are obtained from reaction models. Using nuclear trajectories calculated within the one-body dissipation model give a far too low yield of high-energy δ electrons indicating that the deceleration predicted by this model is too slow. The new dissipative diabatic model, which takes into account a non-Markovian dissipation at the beginning of the collision and which ascribes elastoplastic properties to nuclear matter, is able to reproduce both the fast deceleration and the long nuclear contact time deduced from the experimental data.

Excitation functions were measured for the ${}_{}{}^{45}{}_{}{}^{}\mathrm{Sc}$(n,2n${)}^{44}$${\mathrm{Sc}}^{\mathit{m}}$, ${}_{}{}^{45}{}_{}{}^{}\mathrm{Sc}$(n,2n${)}^{44}$${\mathrm{Sc}}^{\mathit{m}+\mathit{g}}$, and ${}_{}{}^{55}{}_{}{}^{}\mathrm{Mn}$(n,2n${)}^{54}$Mn reactions from threshold to 13 MeV, and for the ${}_{}{}^{45}{}_{}{}^{}\mathrm{Sc}$(n,p${)}^{45}$Ca, ${}_{}{}^{45}{}_{}{}^{}\mathrm{Sc}$(n,α${)}^{42}$K, ${}_{}{}^{55}{}_{}{}^{}\mathrm{Mn}$(n,p${)}^{55}$Cr, and ${}_{}{}^{55}{}_{}{}^{}\mathrm{Mn}$(n,α${)}^{52}$V reactions over the neutron energy range of 6 to 13 MeV. The quasimonoenergetic neutrons were produced via the ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(d,n${)}^3$He reaction using a deuterium gas target at a variable energy compact cyclotron. The activation technique in combination with high resolution γ-ray spectroscopy was used. In the case of the ${}_{}{}^{45}{}_{}{}^{}\mathrm{Sc}$(n,p${)}^{45}$Ca and ${}_{}{}^{55}{}_{}{}^{}\mathrm{Mn}$(n,p${)}^{55}$Cr reaction produces, ‘‘low-level’’ ${\mathrm{\beta }}^{\mathrm{-}}$ counting was applied. The reaction product ${}_{}{}^{45}{}_{}{}^{}\mathrm{Ca}$ was separated radiochemically prior to ${\mathrm{\beta }}^{\mathrm{-}}$ counting. Statistical model calculations taking into account precompound effects were performed for all the reactions studied. The experimental excitation functions are reproduced well by the calculation except for the (n,α) reaction on the ${}_{}{}^{45}{}_{}{}^{}\mathrm{Sc}$ target.

Triple (p-p-fragment) coincidences from the ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$${+}^{58}$Ni reaction at 850 MeV have been measured. By detecting the source of the emitted particles we were able to study the directional dependence of the p-p correlation function. From this dependence both the source size (${\mathit{r}}_0$) and the particle emission time (τ) have been extracted. The extracted p-p correlation functions could be fitted with source size and lifetime in the range of 3.$3_{\mathrm{-}0.7}^{+1.3\mathrm{}}$ fm and 3.$2_{\mathrm{-}2.2}^{+1.3\mathrm{}}$×${10}^{\mathrm{-}22}$ s, respectively.

Momentum spectra have been measured for the reaction ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$${(}^7$Li${,}^8$B${)}^{10}$Li at 130 MeV and laboratory angles of 5° and 3.5°. There is strong evidence for the existence of a broad state in the unstable nucleus ${}_{}{}^{10}{}_{}{}^{}\mathrm{Li}$, corresponding to a single p-wave neutron resonance unbound to neutron decay by 538±62 keV with wdith ${\mathrm{\Gamma }}_{\mathrm{lab}}$=358±23 keV. There is also weak evidence that the ${}_{}{}^{10}{}_{}{}^{}\mathrm{Li}$ ground state may be either an s- or a p-wave resonance barely unbound to neutron decay with ${\mathit{S}}_{\mathit{n}}$≥-100 keV and ${\mathrm{\Gamma }}_{\mathrm{lab}}$<230 keV. The measured Q values for the reaction leading to these states are -32 908±62 keV and greater than -32 471 keV, respectively. A comparison is made with previous measurements and theoretical predictions of the low-lying structure of the neutron-unstable nucleus ${}_{}{}^{10}{}_{}{}^{}\mathrm{Li}$.