Structures in which a neutron occupies an $\Omega =\frac{1}{2}$ orbit with decoupling parameter $a_n\simeq 1$ and a proton is in an $\Omega \ne \frac{1}{2}$ orbit have been found in a doubly odd deformed nucleus. These bands are almost identical to the $\Omega \ne \frac{1}{2}$ bands in neighboring odd proton nuclei. This behavior is reproduced analytically within the two-quasiparticle-plus-rotor model.

Scattering and reaction cross sections in the seven-nucleon system are calculated in a multiconfiguration resonating-group study which consists of t${+}^4$He, n${+}^6$Li, and n${+}^6$${\mathrm{Li}}^{\mathrm{*}}$ cluster configurations. The results show that the diffraction and interference features of the experimental angular distributions can be well explained, but that the calculated magnitudes of the differential cross sections are generally too large. In addition, it is found that the calculated total reaction cross sections for the t${+}^4$He and n${+}^6$Li channels are only 30–40 % of the measured values, indicating that, for a satisfactory explanation of all the important features of the seven-nucleon system, more cluster configurations must still be incorporated into the resonating-group formulation.

Angular distributions of differential cross sections and vector and tensor analyzing powers have been measured for transitions in ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}$(d${,}^3$He${)}^{30}$Si and ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}$(d,t${)}^{30}$P reactions at $E_d$≊16 Mev. Exact, finite-range distorted-wave Born-approximation analyses have been performed using S- and D-state amplitudes for the three-nucleon systems. Calculations have also been carried out by incorporating realistic three-body wave functions. A j dependence in tensor analyzing powers observed for the first time in (d${,}^3$He) and (d,t) reactions, can be reproduced in distorted-wave Born approximation calculations only by including a D-state amplitude for three-nucleon systems. We find that the tensor analyzing powers for j=$l_1$+(1/2 transfers exhibit significantly more pronounced D-state effects than those for j=$l_1$-(1/2 transfers. The analyzing powers along with the differential cross sections have been used to extract spectroscopic factors for the low-lying levels in ${}_{}{}^{30}{}_{}{}^{}\mathrm{Si}$ and ${}_{}{}^{30}{}_{}{}^{}\mathrm{P}$, and the results have been compared with recent sd–shell-model predictions.

Inelastic electron scattering cross sections for ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ have been measured at 180° for incident electron energies of 130 and 200 MeV. Spectra measured up to excitation energies of 54 MeV are relatively featureless and show no evidence for resolvable excitations. The data are compared with continuum shell-model calculations which include all one-body breakup channels.

Measurements of the differential cross sections and analyzing powers have been made for ${}_{}{}^{28}{}_{}{}^{}$Si(n,$n_0$) and ${}_{}{}^{28}{}_{}{}^{}$Si(n,$n_1$) for incident neutron energies between 8 and 17 MeV. These data have been combined with previous differential and total cross-section data to obtain the most complete data set for neutron scattering from ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ over the 8–40 MeV energy range. The data have been described within the framework of a symmetric rotational model using phenomenological coupled-channels calculations. Nuclear moments were deduced and they are in good agreement with those obtained from electron scattering and Coulomb excitation measurements. Various calculations were performed to determine the sensitivity of the data and calculations to the signs of the potential deformation parameters ${\beta }_2$ and ${\beta }_4$. The systematic analysis of the analyzing power data enabled the determination of the deformation length for the spin-orbit potential. Comparisons between neutron- and proton-scattering data and calculations were made to test the sensitivity of this type of data to charge symmetry breaking in the nuclear force and to investigate the isospin dependence of the absorptive part of the nucleon-nucleus scattering potential for ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$. The results of these comparisons suggest that the differences between ${}_{}{}^{28}{}_{}{}^{}$Si+n and ${}_{}{}^{28}{}_{}{}^{}$Si+p scattering can be attributed solely to Coulomb effects.

In this work are presented two new sets of integral equations for studying three-body exchange processes. The two are obtained from the Baer-Kouri-Levin-Tobocman approach by assuming the W matrix, via which the coupling is done, to be dependent on the internal coordinates of the system. In contrast to the channel permuting array structure of the original version of the Baer-Kouri-Levin-Tobocman equations, one set of equations is almost symmetric with respect to the different channels and the other is fully symmetric, thus ensuring a unitary S matrix. The first set of equations has already been solved for a three-channel, three-dimensional system, H+$H_2$ (J=0), and has been found to yield the correct results. Connectivity, as related to these equations, is discussed.

Relativistic models which simulate the two-nucleon system are constructed by means of the one-dimensional two-body Dirac equation, and differences between relativistic and nonrelativistic descriptions are illustrated. The relativistic interaction is assumed to consist of a Lorentz scalar S and the zeroth-component V of a vector; the S is attractive and the V repulsive. This interaction has intriguing features. Unlike the nonrelativistic case, the nucleon-nucleon phase shift can be fitted easily without assuming that the range of the repulsive V is smaller than that of the attractive S. Implications for deuteron structure are examined.

The photodisintegration of the deuteron is investigated with emphasis on the differential cross section D(γ,p)n in the forward direction. However the angular distribution as well as the γ asymmetry are also given. The calculation takes relativistic, pion exchange, and Δ(1232) corrections into account. Nonlocal nucleon-nucleon interactions are treated in a manner in which gauge invariance is respected. The differences between various approximations beyond the Siegert limit are discussed. The role of the D-state probability of the deuteron in the forward direction is studied and the difference of two gauges before and after the inclusion of various corrections are presented. Finally a comparison with experiment is carried out.

The differential cross sections for the (p,n) reaction to the ground-state analogs of the lightest four stable zirconium isotopes (90, 91, 92, and 94) have been measured at proton energies of 18 and 25 MeV. Integrated cross sections are found to deviate from the expected linear dependence on neutron excess as was previously found for the molybdenum isotopes. The observed dependence is in quantitative agreement with calculations, including inelastic couplings used to explain the molybdenum results. The energy dependence of the zirconium analog cross sections confirms the resonant-type enhancement of the low energy (p,n) excitation function observed previously for the molybdenum isotopes.

The neutron total cross section for n+ ${}_{}{}^{86}{}_{}{}^{}$Kr has been measured over the incident neutron energy range 0.015 to 25 MeV. The average total cross section is obtained for neutron energies from 1 to 25 MeV. For the energy region from 0.015 to 1 MeV, an R-matrix analysis yields resonance parameters which provide a complete representation of the neutron scattering functions for the $s_{1/2}$, $p_{1/2}$, and $p_{3/2}$ scattering channels. From this analysis level densities, neutron strength functions, and external R functions are obtained for the 1-MeV energy region just above the neutron separation energy. The backshifted Fermi-gas model provides excellent descriptions of the level densities for the ${(1/2\mathrm{}}^{+}$, ${(1/2\mathrm{}}^{\mathrm{-}}$, and ${(3/2\mathrm{}}^{\mathrm{-}}$ states. Evidence of intermediate structure is found for the s-, p-, and d-wave scattering channels.

Negative parity states of ${}_{}{}^{194}{}_{}{}^{}$,196,198Pt are studied via the analysis of previously reported (p,p’) data. The results suggest that two-quasiparticle configurations built on the nonexcited core play significant roles in the $7_1^{\mathrm{-}}$ states, as predicted by the semidecoupled model and suggested by electron-capture data. It is also found that the $3_1^{\mathrm{-}}$ states can be understood in an octupole vibrational picture. The latter result highlights an anomaly in the behavior of octupole states in the Pt-Hg region.

We report measurements and analyses of cross sections up to 40 MeV for the reactions ${}_{}{}^{89}{}_{}{}^{}(\mathit{p}$,n${)}^{89}$Zr, ${}_{}{}^{89}{}_{}{}^{}(\mathit{p}$,2n${)}^{88}$Zr, and ${}_{}{}^{89}{}_{}{}^{}(\mathit{p}$,pn${)}^{88}$Y obtained by the foil-activation method. The data are compared with other measurements and analyzed by the Hauser-Feshbach plus one- and two-step direct reactions. The analysis shows that Hauser-Feshbach plus one-step direct reaction is adequate to explain the data. The cross sections are also calculated with phenomenological preequilibrium models (exciton, hybrid, and geometry-dependent hybrid models), using global parameters. However, to get a good fit to the data with these phenomenological models, some adjustments of the global parameters were necessary. A discussion on the differences between the direct-reaction theory and preequilibrium models is given.

The hexadecapole transition strength distribution is measured for the deformed nucleus ${}_{}{}^{150}{}_{}{}^{}\mathrm{Nd}$ using the (p,p’) reaction at $E_p$=30 MeV. The experimental information on B(E4) values in this nucleus and in ${}_{}{}^{156}{}_{}{}^{}\mathrm{Gd}$ is interpreted in the framework of the sdg interacting boson model. It is found that the main features of the experimental data are fairly well reproduced by a Hartree-Bose method plus Tamm-Dancoff approximation.

Measurements of α-particle spectra in (n,α) reactions induced on ${}_{}{}^{142}{}_{}{}^{}$,143,144Nd by neutrons with energy between ≊12 and 20 MeV are presented. The spectra are greatly affected by the shell structure of the target nucleus. A semi-microscopic calculation made in the framework of the pickup model, assuming dominance of transitions to neutron-hole states of the residual nucleus, provides a satisfactory reproduction of the data. Transitions to single neutron states through a knockout process have also been considered, but it is found that they may only slightly contribute to the measured α-particle yield.

Radiochemical activation techniques were used to study the behavior of projectile fragments formed in the interaction of 0.9A and 1.8A GeV ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ ions within thick Cu targets. Two identical 1 cm thick Cu disks were irradiated with separations between the disks of 0, 10, and 20 cm, respectively. The results show an enhancement in the formation of light mass (A<30) radioactive residues in the second disk relative to the first in the contact configuration for both projectile energies. This enhancement decreases for increasing distance between the Cu disks. While our results with 0.9A GeV projectiles can be explained within the framework of conventional nuclear physics, the data at 1.8A GeV demand that either secondaries of Z=1, neutrons and/or pions are emitted with surprisingly large transverse momenta, or that some projectile fragments have large interaction cross sections but decay in flight (τ∼${10}^{\mathrm{-}10}$ s).

Coupled channels calculations are presented for the reaction of 1120 and 1400 MeV ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ ions on ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ using a deformed optical model. For scattering angles corresponding to the grazing angle in the 1400 MeV case, the cross-section flux is evenly distributed in a central plateau of final spin states.

Differential cross sections have been measured for the elastic and inelastic scattering of ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ from ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ at 352 MeV. An optical model analysis has been performed for the elastic scattering data. Considerable ambiguity was found. Potentials which are either transparent or strongly absorbing in the surface region were obtained which give equally good fits to the data. The combined elastic and inelastic data were subjected to a coupled-channels analysis and the ambiguity was found to persist, in contrast to previously reported one-nucleon transfer data whose analysis allowed us to discriminate between the two types of potential. Other characteristics of the scattering are discussed.

Fission and fusion barriers have been calculated for decay or formation of the composite nuclei ${}_{}{}^{149}{}_{}{}^{}\mathrm{Tb}_{}^{\mathrm{*}}{}_{}{}^{}$ and ${}_{}{}^{194}{}_{}{}^{}\mathrm{Hg}_{}^{\mathrm{*}}{}_{}{}^{}$ via the Yukawa-plus-exponential-finite-range macroscopic model. The predicted properties of these barriers are used for comparisons to measured total kinetic energies for the emission of light fragments (2≤$Z_L$≤9) and to empirical systematics of s-wave fusion barrier heights. The fusion barriers are consistent with the model. Values of total kinetic energies were calculated with the assumption of no energy loss into excitation beyond the saddle point. For each light fragment, the observed values of total kinetic energies are smaller than those calculated. The deviation increases with $Z_L$ and is correlated with the nuclear shape at the corresponding conditional saddle point. It scales with the neck thickness and the fragment deformation, as does the error involved in our approximation. This suggests (at least for the higher $Z_L$ values) that this macroscopic fission model might apply for light-fragment emission. Dynamical effects must, however, be included.

New high spin states in ${}_{}{}^{25}{}_{}{}^{}\mathrm{Mg}$ (up to 13.3 MeV in excitation) have been located using the ${}_{}{}^{12}{}_{}{}^{}\mathrm{N}$,pγ${)}^{25}$Mg reaction at a laboratory beam energy of 23.5 MeV. Gamma decay from 28 neutron unbound levels has been observed (24 of which are reported here for the first time) up to 7 MeV above the neutron drip line. Tentative identification of the yrast line up to ${(17/2\mathrm{}}^{+}$ has been made, along with an extension of the ground-state rotational band up to ${(15/2\mathrm{}}^{+}$ and the location of several other states with $J^{\pi }$${=(11/2\mathrm{}}^{+}$ and ${(15/2\mathrm{}}^{+}$. Extensive comparison with the s-d shell model and the cranked Nilsson-Strutinsky model has been made for the states in ${}_{}{}^{25}{}_{}{}^{}\mathrm{Mg}$. Very good agreement is observed between the shell model and experimental level energies and γ-decay branches. Potential energy surfaces for $J^{\pi }$${=(11/2\mathrm{}}^{+}$, ${(13/2\mathrm{}}^{+}$, and ${(17/2\mathrm{}}^{+}$ in the cranked Nilsson-Strutinsky model show a noncollective oblate local minimum at (${\epsilon }_2$,γ)=(0.34,60°) for ${(11/2\mathrm{}}^{+}$ and prolate configurations at (0.2,-120°) for ${(13/2\mathrm{}}^{+}$ and ${(17/2\mathrm{}}^{+}$. These states compete with the collective ground-state band members at γ≊0° and become yrast for ${(17/2\mathrm{}}^{+}$. The stabilization of these prolate aligned states relative to more deformed, collective states of the same spin results from shell effects at high spin in the cranking model, and provides a description of the configuration in the yrast $8^{+}$; ${(11/2\mathrm{}}^{+}$, ${(13/2\mathrm{}}^{+}$, and ${(17/2\mathrm{}}^{+}$; and $4^{+}$ states in ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$, ${}_{}{}^{25}{}_{}{}^{}\mathrm{Mg}$, and ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$, respectively.

The electromagnetic dissociation of ${}_{}{}^{59}{}_{}{}^{}\mathrm{Co}$ and ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$ target nuclei by 1.26 GeV/nucleon ${}_{}{}^{139}{}_{}{}^{}\mathrm{La}$ projectiles was inferred from measurement of cross sections for the one-neutron removal reaction. The corresponding electromagnetic dissociation cross sections are large, reaching 0.28±0.04 and 1.97±0.13 barns for the ${}_{}{}^{59}{}_{}{}^{}\mathrm{Co}$${(}^{139}$La,X${)}^{58}$CO and ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$${(}^{139}$La,X${)}^{196\mathrm{A}\mathrm{u}}$ reactions, respectively. The experimental cross sections in excess of the estimated nuclear contributions are generally well described by use of the Weizsäcker-Williams method for calculating the electromagnetic dissociation contributions, but they appear to increase more slowly as the projectile charge is increased, consistent with a trend observed earlier for lower-Z projectiles.