The reaction ${}_{}{}^{52}{}_{}{}^{}\mathrm{Cr}$(p,γ${)}^{53}$Mn has been studied in the proton energy range 1.38–1.66 MeV (7.91<${\mathit{E}}_{\mathit{x}}$<8.19 MeV). Spectra and γ-ray angular distributions at 16 of the 33 resonances provide ${\mathit{J}}^{\mathrm{\pi }}$ assignments and γ decay schemes for these and many of the bound states. Eight fragments of the isobaric analog of the ${}_{}{}^{53}{}_{}{}^{}\mathrm{C}$ 5/$2^{\mathrm{-}}$ 1.006-MeV state were found near ${\mathit{E}}_{\mathit{x}}$=8.05 MeV. Isobaric analog state centroids and widths are presented for the strong γ-decay channels and are related to the structure of the parent state.

High-spin states in the doubly odd nucleus ${}_{}{}^{138}{}_{}{}^{}\mathrm{Pm}$ have been studied via gamma-ray spectroscopic methods following the ${}_{}{}^{116}{}_{}{}^{}\mathrm{Cd}$${(}^{27}$Al,5nγ) heavy-ion fusion-evaporation reaction. Several rotational bands have been populated in the nucleus. The yrast cascade is based on two signature components of the π${\mathit{h}}_{11/2}$⊗ν${\mathit{h}}_{11/2}$ configuration. A sideband was observed, which is probably based on the π[413]5/$2^{+}$⊗ν${\mathit{h}}_{11/2}$ configuration. Similar rotational bands built on these configurations have been observed in the neighboring doubly odd ${}_{}{}^{134}{}_{}{}^{}\mathrm{Pr}$ and ${}_{}{}^{136}{}_{}{}^{}\mathrm{Pm}$ nuclei. An additional ΔI=2 band structure, not observed in these other nuclei, has also been populated. At low rotational frequencies, this band is possibly based on the π${\mathit{h}}_{11/2}$⊗ν[400]1/$2^{+}$ configuration. At a frequency ħω∼0.31 MeV it is crossed by a band based on the favored signature of the π${\mathit{h}}_{11/2}$⊗ν${\mathit{i}}_{13/2}$ configuration with an accompanying gain in alignment of ∼6ħ.

Kinematically complete measurements of the ${}_{}{}^1{}_{}{}^{}\mathrm{H}$(α${,}^3$He p)n reaction at ${\mathit{E}}_{\mathrm{\alpha }}$=170 MeV were made at several ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ and proton angles. Assuming an incoherent sum of different multipole contributions in different reaction channels, it was possible to describe all measured spectra consistently, taking into account sequential decay of states in ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^4{}_{}{}^{}\mathrm{Li}$ and the p-n final state interaction. The parameters used to describe the p-n final state interaction and excited states in ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ are consistent with previous measurements. Resonance energies and widths for the ground state and the first excited state of ${}_{}{}^4{}_{}{}^{}\mathrm{Li}$ were extracted which are considerably lower than assumed so far. The measured cross sections are in agreement with distorted-wave Born approximation calculations using folding form factors.

The atomic mass excesses of ${}_{}{}^{181}{}_{}{}^{}\mathrm{Re}$ and ${}_{}{}^{181}{}_{}{}^{}\mathrm{Os}$ were determined to be -46.519±0.016 and -43.49±0.20 MeV from the measured Q value of -26.480±0.014 MeV for the ${}_{}{}^{185}{}_{}{}^{}\mathrm{Re}$(α${,}^8$He${)}^{181}$Re(g.s.) reaction and the known beta-decay Q value. The results were compared with some predicted values.

Lifetimes of ${\mathit{T}}_{1/2}$=88(3) and 291(11) ps were measured for the $0_2^{+}$ states and ${\mathit{T}}_{1/2}$=102(3) and 500(13) ps for the $4_1^{+}$ states in ${}_{}{}^{92.94}{}_{}{}^{}\mathrm{Zr}$, respectively, using a recently developed β-γ-γ fast timing method. The observed B(E2) values and the recently measured g factors for the $2_1^{+}$ states in ${}_{}{}^{92,94}{}_{}{}^{}\mathrm{Zr}$ deviate strongly from properties of a pure ν1${\mathit{d}}_{5/2}$ multiplet and even from the π(1${\mathit{p}}_{1/2}$,0${\mathit{g}}_{9/2}$)ν(1${\mathit{d}}_{5/2}$,2${\mathit{s}}_{1/2}$) shell-model results of Gloeckner. The experimental results are reproduced, however, by spherical shell model calculations with a model space of π(0${\mathit{f}}_{5/2}$,1${\mathit{p}}_{3/2}$,1${\mathit{p}}_{1/2}$,0${\mathit{g}}_{9/2}$)ν (1${\mathit{d}}_{5/2}$,2${\mathit{s}}_{1/2}$,1${\mathit{d}}_{3/2}$,0${\mathit{g}}_{7/2}$) and provide compelling evidence for important contributions of π${\mathit{f}}_{5/2}$,${\mathit{p}}_{3/2}$ orbits to the low-energy structure of these nuclei.

In a series of experiments, we have reinvestigated the decay of the doubly magic nucleus ${}_{}{}^{56}{}_{}{}^{}\mathrm{Ni}$, which is believed to be copiously produced in supernovae. We have confirmed its previously known decay scheme and half-life, and have searched for several rare decay modes. We establish an upper limit of 5.8×${10}^{\mathrm{-}7}$ for the branching ratio of the second forbidden unique ${\mathrm{\beta }}^{+}$ decay to the 158-keV level in ${}_{}{}^{56}{}_{}{}^{}\mathrm{Co}$, leading to a lower limit of 2.9×${10}^4$ yr for the half-life of fully ionized ${}_{}{}^{56}{}_{}{}^{}\mathrm{Ni}$ nuclei in cosmic rays. We also establish an upper limit of 5.0×${10}^{\mathrm{-}3}$ for the branching ratio of the isospin forbidden Fermi electron capture transition to the 1451-keV level in ${}_{}{}^{56}{}_{}{}^{}\mathrm{Co}$, which in turn leads to an upper limit of 124 keV for the isospin mixing Coulomb matrix element of the ${}_{}{}^{56}{}_{}{}^{}\mathrm{Ni}$ ground state.

Mean lifetimes of the first 5/$2^{+}$ and 9/$2^{+}$ states in the mirror nuclei ${}_{}{}^{23}{}_{}{}^{}\mathrm{-}_{}^{23}{}_{}{}^{}$Mg have been measured by application of the Doppler-shift attenuation method and the reactions ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{12}$C,p${)}^{23}$Na, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{15}$N,α${)}^{23}$Na, and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{12}$C,n${)}^{23}$Mg. The results are 1800±110 and 1570±170 fs (5/$2^{+}$), and 139±10 and 91±12 fs (9/$2^{+}$) for ${}_{}{}^{23}{}_{}{}^{}\mathrm{Na}$ and ${}_{}{}^{23}{}_{}{}^{}\mathrm{Mg}$, respectively. For the effective stopping of recoils, the targets were prepared by implanting ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ into Ta backings. The Monte Carlo method and experimentally confirmed electronic and nuclear stopping powers were used in the Doppler-shift attenuation analysis. The experimental transition strengths are compared with the predictions of recent shell-model calculations.

The level scheme of ${}_{}{}^{111}{}_{}{}^{}\mathrm{Cd}$ has been studied by measuring singles and coincident γ-ray spectra following neutron capture by ${}_{}{}^{110}{}_{}{}^{}\mathrm{Cd}$. Despite good experimental conditions, only six γ rays were observed. The intensity balances at the 396-, 342-, and 245-keV levels are discussed. The results support the assumption that the 284-keV γ ray, emitted from the 680-keV state, is the dominant population mode of the 49-min isomer at 396 keV.

Lifetimes of states in ${}_{}{}^{75}{}_{}{}^{}\mathrm{Kr}$, excited in the ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}$${(}^{24}$Mg,2pn${)}^{75}$Kr reaction at 75 MeV, have been measured using the recoil-distance technique. The E2 transition strengths in ${}_{}{}^{75}{}_{}{}^{}\mathrm{Kr}$ have been interpreted within the rigid-triaxial-rotor–plus–quasiparticle model. A consistent set of parameters, required for the application of this model, has been obtained from a systematic study of Kr isotopes. The prediction of the model describes the experimental data rather well and suggests a deformation of β≊0.4 for ${}_{}{}^{75}{}_{}{}^{}\mathrm{Kr}$.

The off-shell variations in the electromagnetic form factors of an off-shell nucleon are calculated by considering the one-pion loop corrections to the vector meson dominance model. For the pion-nucleon interaction the pseudoscalar as well as the pseudovector coupling are considered. Meson-nucleon vertices with strong form factors are assumed and current operators are used, which satisfy Ward-Takahashi identities. Typical variations of only a few percent are found for the em form factors of the proton. Off-shell sensitivities in the kinematic situations of elastic and inelastic scattering on nuclei are considered.

The quantum correction to the Vlasov equation is considered using the Wigner transform of the time-dependent Hartree-Fock equation without truncation in ħ order. Decomposing the Wigner function in terms of test particles with the form factor in a phase space, quantum extension of the Vlasov equation determines the equation of motion of the test particle which follows classical dynamics. The discrimination between the quantum and classical limits is related to a density matrix condition which constrains the distribution of test particles.

Centroids of the effective nucleon-nucleon interaction for the mass region A=28–64 are extracted directly from experimental single-particle spectra, by comparing single-particle energies relative to different cores. Uncertainties in the centroids are estimated at approximately 100 keV, except in cases of exceptional fragmentation of the single-particle strength. The use of a large number of inert cores allows the dependence of the interaction on mass or model space to be investigated. The method permits accurate empirical modifications to be made to realistic interactions calculated from bare nucleon-nucleon potentials, which are known to possess defective centroids in many cases. In addition, the centroids can be used as input to the more sophisticated fitting procedures that are employed to produce matrix elements of the effective interaction.

The depletion of the neutron hole strength of 2${\mathit{f}}_{7/2}$ state at 2.34 MeV excitation energy in ${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$ has been explained on the basis of the core polarization effect after retrieving the energies of the shell-model neutron hole states in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ from a numerical solution of the Schrödinger equation. The present findings are discussed in the light of other existing theoretical calculations.

The validity of the rotational model expressions relating the E4 transition probabilities and the intrinsic hexadecupole moments is examined in the light of the recent data on the inelastic electron-scattering form factors for the $0^{+}$→$4^{+}$ transitions in some medium-mass nuclei.

Squeeze-out, a component of the collective flow of nuclear matter, is the preferential emission of particles out of the reaction plane. Using the sphericity method the out-of-plane/in-plane ratio of the kinetic energy flow has been analyzed as a function of multiplicity and beam energy for Ca+Ca, Nb+Nb, and Au+Au collisions measured with the Plastic Ball detector at the Bevalac. Also, azimuthal distribution of the particles around the flow axis are presented together with the extracted out-of-plane/in-plane ratios. Finally, the rapidity dependence of the out-of-plane/in-plane ratio has been investigated with a new method using the transverse momentum components of the particles.

A framework based on a full-folding model of the nucleon optical potential is presented for studying nuclear densities of closed-shell nuclei using intermediate energy nucleon scattering. Using a density-matrix expansion for the mixed density, a simplified optical potential is obtained that retains the energy and momentum dependence of the effective interaction prescribed by the full-folding model. The interplay between the local density, nonlocality of the mixed-density and off-energy-shell degrees of freedom in the full-folding approach to nucleon scattering is made relatively transparent. The validity of the proposed framework is established for momentum transfers out to ∼2.5 ${\mathrm{fm}}^{\mathrm{-}1}$ in p${+}^{16}$O and p${+}^{40}$Ca scattering at energies between 200 and 400 MeV. The sensitivity of the scattering observables to nuclear densities is investigated.

We compute the analyzing power, ${\mathit{A}}_{\mathit{y}}$, and spin rotation, Q, for proton elastic scattering at 650 and 800 meV from target nuclei ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$, using both nonrelativistic multiple-scattering theory and a relativistic impulse approximation model. We show that the nonrelativistic theory, based on the Schrödinger equation with relativistic kinematics, and the relativistic model, based on the Dirac equation, provide very similar and equally good descriptions of these spin observables when electromagnetic spin-orbit contributions are included in both approaches. The nonrelativistic model calculations include contributions from nuclear medium effects (Pauli blocking and binding energy corrections) and also target nucleon two-body correlations. Medium effects and correlations are not expected to be significant in the relativistic model based on the Dirac equation, and were not included.

The process of rapid massive cluster formation at low densities is associated with the process of multifragmentation. This phenomenon is studied by comparing the free energy for internally formed clusters with the free energy of the homogeneous system. The importance of considering two freeze-out conditions (entropy-freeze-out and force-freeze-out) in the dynamics leading to multifragmentation is discussed. Calculations of the yield of intermediate mass fragments are made with the expanding-evaporating source model and compared with data. The consequences of distributions in excitation energy, on the observation of multifragmentation, are discussed.

A simple semiempirical relation for the prediction of the partial alpha half-life of the favored transition in even-even nuclides has been successfully derived. Correction factors for the closed shells, N=126 or Z=82, were also obtained. Hindrance factors for odd-A and odd-odd nuclides were obtained from the relation for even-even nuclides and discussed. Alpha partial half-lives of nuclides of transactinides and superheavy elements have been predicted for the ground-to-ground state favored transitions.

Two techniques that enable us to calculate cross sections of complete fusion and various incomplete fusion reactions within the framework of direct reaction theories are combined to calculate cross sections of various reactions initiated by d${+}^{93}$Nb with two incident energies of 15 and 25.5 MeV. It is shown that the predicted cross sections agree well with existing experimental data. This study provides a rather critical test of the two techniques used by examining the consistencies of the predictions of the total incomplete fusion plus direct reaction cross sections and also the regions where these reactions predominantly take place. One of these techniques can be easily used with any optical model code to obtain compound nucleus cross sections (excluding breakup and other direct reaction cross sections) for the Hauser-Feshbach calculations involving deuteron-induced reactions.