In this paper the Gibbs free energy in statistical physics is used to study the liquid-gas phase transition in finite and asymmetric nuclear matter. The liquid-gas phase diagrams for the general nuclear matter with the Skyrme interaction are presented.

A new calculation of the predominantly isoscalar PNC matrix element between the ${\mathit{J}}^{\mathrm{\pi }}$T $0^{+}$1,$0^{\mathrm{-}}$1 (${\mathit{E}}_{\mathit{x}}$≊8.7 MeV) states in ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ has been carried out in a (0+1+2+3+4)ħω model space with the Warburton-Brown interaction. The magnitude of the PNC matrix element of 0.22 to 0.54 eV obtained with the DDH PNC interaction is substantially suppressed compared with previous calculations in smaller model spaces but shows agreement with the preliminary Seattle experimental data. The calculated sign is opposite to that obtained experimentally, and the implications of this are discussed.

We introduce boson mappings of the fermion dynamical symmetry model (FDSM) to investigate and clarify the relation between the FDSM and the proton-neutron interacting boson model (IBM). The Dyson boson mapping is employed in a dual role—it is first used to obtain exact FDSM results and then as the starting point to obtain some hermitized mappings. By hermitizing the Dyson boson image of the FDSM Hamiltonian through a seniority dictated similarity transformation or by using a Belyaev-Zelevinsky mapping and retaining in both instances one- and two-body terms only, one obtains an IBM type Hamiltonian. FDSM and boson mapped results are then compared for a few typical cases. We reexamine, from the boson point of view, recent statements about an effective SO(6) symmetry when ${}_{}{}^{196}{}_{}{}^{}\mathrm{Pt}$ is analyzed in the FDSM and about the appearance of normal (maximal F-spin) and exotic states in an application of the FDSM to ${}_{}{}^{134}{}_{}{}^{}\mathrm{Ba}$. Throughout our analysis possible spurious states, which may appear as a result of an effective overcompleteness in the (linearly independent) boson basis, are properly identified. We discuss when and where these states appear in the spectra, and the possible implications these considerations may have for allowed representations in the IBM and FDSM.

The multicluster generator coordinate method is applied to a microscopic study of the ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ spectroscopy and of the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$(α,γ${)}^{20}$Ne capture cross section. The ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ nucleus is described by four α clusters located on the apexes of a tetrahedron. The good quantum numbers of the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and α${+}^{16}$O wave functions are restored by a multiple angular-momentum projection. With respect to the usual two-center approach, where ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ is described by a closed p shell, the five-α model improves different ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ spectroscopic properties. The ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$(α,γ${)}^{20}$Ne S factor is reduced by about 30% at astrophysical energies.

The properties of light even and odd Xe and Ba nuclei (N and Z close to 56) with respect to octupole deformation have been studied by the Hartree-Fock+BCS and the generator coordinate methods. None of the considered nuclei possess a stable static octupole deformation. However, we find that octupole collectivity is enhanced by dynamical correlations. Cranked shell model calculations indicate that octupole effects should persist at least up to spins around 10ħ.

The dependence of nuclear shape transition on changes in the nuclear volume in ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ has been studied within the framework on the constrained finite temperature Hartree-Fock approximation. The deformation parameters β and γ are very sensitive to changes in the nuclear volume. A first-order shape transition in ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ takes place at the temperature of 1 MeV and at the volume of ${\mathit{V}}_{\mathit{c}}$=1.025${\mathit{V}}_0$, where ${\mathit{V}}_0$ is the zero temperature unconstrained volume of the system. Previously we have shown that a 2.5% compression of the system yields a downward shift in the critical temperature of 0.7 MeV. Similarly a 2.5% expansion of the system also yields a decrease in the critical temperature of 0.3 MeV. Finally a compression of the system leads to a corresponding reduction in the magnitude of the level density, while an expansion increases its value only slightly.

The linearized collective Schrödinger equation for nuclear quadrupole vibrations describes nuclei with spin 3/2 in the ground state. Another model, which has been developed for nuclei with spin 3/2, is the j=3/2 interacting boson fermion model. We use a special property of the Clifford algebra, which appears in the linearized collective Schrödinger equation, to establish a connection between both models. We also compare the predictions of both approaches for various spin-3/2 nuclei.

The comparison of bosonic and fermionic descriptions of collective nuclear structure are given within the framework of algebraic models. Despite the lack of the F spin in the fermion picture, unification of normal and exotic states can be achieved by the n-p quadrupole interactions. Results for the ${}_{}{}^{134}{}_{}{}^{}\mathrm{Ba}$ are used to illustrate the physics.

A simple method for calculating the asymptotic D-state observables for light nuclei is suggested. The method exploits the dominant clusters of the light nuclei. The method is applied to calculate the ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ asymptotic D to S normalization ratio ${\mathrm{\rho }}^{\mathrm{\alpha }}$ and the closely related D-state parameter ${\mathit{D}}_2^{\mathrm{\alpha }}$. The study predicts a correlation between ${\mathit{D}}_2^{\mathrm{\alpha }}$ and ${\mathit{B}}_{\mathrm{\alpha }}$, and between ${\mathrm{\rho }}^{\mathrm{\alpha }}$ and ${\mathit{B}}_{\mathrm{\alpha }}$, where ${\mathit{B}}_{\mathrm{\alpha }}$ is the binding energy of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$. The present study yields ${\mathrm{\rho }}^{\mathrm{\alpha }}$≃-0.14 and ${\mathit{D}}_2^{\mathrm{\alpha }}$≃-0.12 ${\mathrm{fm}}^2$ consistent with the correct experimental ${\mathrm{\eta }}^{\mathit{d}}$ and the binding energies of the deuteron, triton, and the α particle, where ${\mathrm{\eta }}^{\mathit{d}}$ is the deuteron D-state to S-state normalization ratio.

Using the scaling model, we calculate within the framework of relativistic Hartree theory the nuclear breathing-model energies corresponding to the NL1 and NL-SH parameter sets of the nonlinear σ-ω-ρ model. Both of these sets are found to be in disagreement with experiment and there is a clear need for an improved fit. However, as far as the nuclear-matter incompressibility ${\mathit{K}}_{\mathit{v}}$ is concerned, neither the NL1 value, 212 MeV, nor the NL-SH value, 356 MeV, can be excluded.

Nuclear level densities play an important role in nuclear reactions such as the formation of the compound nucleus. We develop a microscopic calculation of the level density based on a combinatorial evaluation from a realistic single-particle level scheme. This calculation makes use of a fast Monte Carlo algorithm allowing us to consider large shell model spaces which could not be treated previously in combinatorial approaches. Since our model relies on a microscopic basis, it can be applied to exotic nuclei with more confidence than the commonly used semiphenomenological formuals. An exhaustive comparison of our predicted neutron s-wave resonance spacings with experimental data for a wide range of nuclei is presented.

Decay neutrons from the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$(e,e’n${)}^{39}$Ca reaction were studied in the giant resonance region. The cross sections and angular distributions, separated for ${\mathit{n}}_0$ and ${\mathit{n}}_1$ decays, were obtained for excitation energies between 19 and 27 MeV, at the effective momentum transfer of 0.35 ${\mathrm{fm}}^{\mathrm{-}1}$. Legendre polynomial coefficients obtained from fitting the data are compared with those from the (e,e’p) reaction. In the energy range 19–21 MeV, the interference coefficients ${\mathit{b}}_1$ and ${\mathit{b}}_3$ for the ground state transition are in agreement, but the noninterference coefficient ${\mathit{b}}_2$ is different. The different behavior of the angular distribution for protons and neutrons may suggest the interference of the decay from a T=0 quadrupole resonance and the T=1 giant dipole resonance. A similar tendency was also seen in comparing with the (e,e’${\mathit{p}}_1$) reaction. The Legendre polynomial coefficients for the ${\mathit{n}}_0$ decay in the (e,e’n) reaction, transformed to the photon point, agree well with those of the (γ,${\mathit{n}}_0$) reaction. The reduced total cross section is consistent between the (e,e’n) and (γ,n) reactions, but the cross section for (e,e’${\mathit{n}}_0$) is larger than that of (γ,${\mathit{n}}_0$) near the peak of the resonance. The values of the longitudinal-transverse interference term are close to zero in the present region, which is rather small compared with the value near the resonance of the (e,e’p) reaction.

Impact-parameter filtered longitudinal and transverse two-proton correlation functions measured for 36Ar+ 45Sc collisions at E/A=80 MeV are compared to predictions of the BUU transport model. For a cut on large transverse energies, the overall trends of the measured correlated functions are rather well reproduced by calculations for central collisions. Systematic discrepancies become visible, however, for calculations with larger impact parameters.

Reaction cross sections for alpha particles have been measured for ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$, ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$, ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$, ${}_{}{}^{60}{}_{}{}^{}\mathrm{Ni}$, ${}_{}{}^{124}{}_{}{}^{}\mathrm{Sn}$, and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ at 74.5, 103.2, 129.3, 159.7, and 192.7 MeV. The experimental values are found to be considerably smaller than predictions from conventional optical model calculations.

Velocity spectra, angular, and mass distributions of the evaporation residues produced in the reaction ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$${+}^{12}$C at E${(}^{28}$Si)=104, 115, and 154 MeV have been measured in the angular range 2.5°≤${\mathrm{\vartheta }}_{\mathit{L}}$≤14°. The results show for all the studied bombarding energies the presence of small contributions of incomplete fusion reactions. These small incomplete fusion components present in the evaporation residue cross sections appear to be due to a cluster transfer reaction mechanism. Similar results have been obtained bombarding a ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ target. The obtained results are compared with earlier measurements and the predictions of some existing models.

In-plane and out-of-plane angular correlations of fission fragments detected in coincidence with projectilelike residues produced in the nuclear collisions ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$${+}^{238}$U at 110 MeV have been investigated. The data present the essential features of a targetlike sequential fission process. A quantitative description of the experimental angular anisotropies requires the storage in the fissioning nucleus of a mean angular momentum in agreement with a dominant mass transfer mechanism.

Analyzing powers ${\mathit{A}}_{\mathit{y}}$ were measured for ${\mathrm{\pi }}^{+}$ and ${\mathrm{\pi }}^{\mathrm{-}}$ elastic scattering from polarized ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ at incident pion energies ${\mathit{T}}_{\mathrm{\pi }}$ near the ${\mathit{P}}_{33}$ π-nucleon resonance. At ${\mathit{T}}_{\mathrm{\pi }}$=130 MeV, the values of ${\mathit{A}}_{\mathit{y}}$ are significantly different from zero for ${\mathrm{\pi }}^{\mathrm{-}}$ scattering. For ${\mathrm{\pi }}^{+}$ at ${\mathit{T}}_{\mathrm{\pi }}$=130 MeV and for both ${\mathrm{\pi }}^{\mathrm{-}}$ and ${\mathrm{\pi }}^{+}$ at all other energies, the ${\mathit{A}}_{\mathit{y}}$ are mostly consistent with zero. Elastic differential cross sections were measured using an unpolarized ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ target. Both the analyzing-power and cross-section data were compared with predictions using a variety of nuclear structure and reaction models. The analyzing power was found to be strongly sensitive to the quadrupole spin-flip part of the transition. The data of this work complement measurements of the magnetic form factor by electron scattering. The pion ${\mathit{A}}_{\mathit{y}}$ data are not reproduced by calculations using wave functions that fit the magnetic form factor at low momentum transfers.

We report asymmetries in the forward-angle differential cross sections for pion single-charge-exchange scattering from oriented and unoriented ${}_{}{}^{165}{}_{}{}^{}\mathrm{Ho}$ nuclei. These asymmetries are directly related to the neutron deformation of a nucleus that has a large charge quadrupole moment. The measured asymmetry extrapolated to 0° is -0.020±0.024. In the model of Chiang and Johnson, this value implies a quadrupole deformation ratio ${\mathrm{\beta }}_2^{\mathit{n}}$/${\mathrm{\beta }}_2^{\mathit{p}}$=0.84±0.08, indicating that the excess neutrons are less deformed than the protons. This result conflicts with the predictions of the best available Hartree-Fock models based on Skyrme interactions. We also report on asymmetries of the nonresonant continuum and of the giant dipole resonances.

Angular distributions of differential cross section and vector analyzing power have been measured for the elastic and inelastic scattering of polarized ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ by ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$ at 60 MeV bombarding energy. The data have been compared with the results of coupled-channels calculations using phenomenological potentials and coupling strengths derived from inelastic scattering cross-section data and B(E2) values. The data are reproduced by calculations including couplings between the ground and excited states of the projectile.

Coulomb-nuclear interference effects were investigated in the inelastic scattering of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ by ${}_{}{}^{64}{}_{}{}^{}\mathrm{Zn}$. Measurements of elastic and inelastic angular distributions of ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ were performed at a laboratory energy of 49 MeV, over the angular range from ${\mathrm{\theta }}_{\mathrm{lab}}$∼30° to 85°. The excitation functions of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ ions were measured at incident energies between 29 and 46 MeV at ${\mathrm{\theta }}_{\mathrm{lab}}$=174°. The experimental angular distributions show structures which are more pronounced for projectile excitation than for target excitation. The interference minimum for the excitation of the ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ first $2^{+}$ state was found to be shifted towards forward angles by approximately 5° (c.m.) with respect to the distorted-wave Born approximation calculations and by approximately 3.5° (c.m.) with respect to the coupled-channels calculations. A pronounced Coulomb-nuclear interference minimum was seen in the excitation of ${}_{}{}^{64}{}_{}{}^{}\mathrm{Zn}$($2^{+}$) state by inelastic scattering of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ projectiles, whereas no pronounced minimum was observed in target excitation by ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ projectiles. The elastic scattering data were analyzed with the optical model. The inelastic differential cross sections for the excitation of the first $2^{+}$ states in the target and in the ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ projectile were analyzed using the distorted-wave Born approximation and also the coupled-channels approach with collective form factors.