Fusion reaction cross sections are calculated for the ${}_{}{}^{40}{}_{}{}^{}{+\mathrm{}}^{40}$,44,48Ca systems taking into account their low lying collective excitations. The remaining differences with the low energy data are interpreted as being due to coupling effects of transfer reaction channels which increase strongly for the ${}_{}{}^{40}{}_{}{}^{}{+\mathrm{}}^{44}$,48Ca cases. Estimates for the observable transfer cross sections are given.

Properties of high spin states in ${}_{}{}^{128}{}_{}{}^{}\mathrm{Ce}$ have been measured following the reaction ${}_{}{}^{112}{}_{}{}^{}\mathrm{Cd}$${(}^{20}$Ne, 4n${)}^{128}$Ce induced by 103-MeV ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ ions. High efficiency γ-γ coincidence measurements and angular distribution measurements showed a series of stretched E2 transitions that form the yrast sequence up to I${=24\mathrm{}}^{+}$, six stretched E2 transitions which form one sideband, and four transitions of undetermined multipolarity forming a second sideband.

The distinction between the information necessary to evaluate calibration of a ${}_{}{}^{81}{}_{}{}^{}\mathrm{Br}$ solar neutrino detector and that necessary to determine the absolute ${}_{}{}^{81}{}_{}{}^{}\mathrm{-}_{}^{81}{}_{}{}^{}$Br mass difference is pointed out.

Energy division between colliding nuclei in damped collisions is studied in the statistical nucleon exchange model. The reactions ${}_{}{}^{56}{}_{}{}^{}\mathrm{Ho}$ and ${}_{}{}^{56}{}_{}{}^{}$Fe${+\mathrm{}}^{238}$U at incident energy of 465 MeV are considered for this purpose. It is found that the excitation energy is approximately equally shared between the nuclei for the peripheral collisions and the systems slowly approach equilibrium for more central collisions. This is in conformity with the recent experimental observations. The calculated variances of the charge distributions are found to depend appreciably on the temperature and are in very good agreement with the experimental data.

Lifetimes of high-spin states in ${}_{}{}^{160}{}_{}{}^{}$,161Yb have been measured by the recoil-distance technique and, from these, changes in the nuclear shape due to the alignment of quasiparticles have been deduced. It is observed that the addition of the favored $i_{13/2}$ quasineutron causes a reduction in collectivity at large rotational frequencies. This reduction is interpreted as due to induced triaxiality and is much larger than predicted by theory.

Resonant parameters ($J^{\pi }$,$E_{\alpha }$,Γ,${\Gamma }_{\alpha }$/Γ) for 67 natural-parity levels in ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ result from the analysis of new high-resolution ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$(α,${\alpha }_0$${)\mathrm{}}^{16}$O data. Accurate absolute differential cross sections were measured simultaneously at 19 angles for alphas scattered by thin ${\mathrm{O}}_2$ gas targets in a differentially-pumped scattering chamber. High resolution beams and small energy steps (Δ$E_{\alpha }$∼5 keV) permitted observation of narrow resonances in the range 9.2<$E_{\alpha }$<13.5 MeV (12.0<$E_x$<15.5 MeV). In addition, near $E_{\alpha }$=9.6 MeV ($E_x$=12.44 MeV), a pair detector measured the total cross section to the $0^{+}$ state in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ at 6.05 MeV. The pair data confirm a previously observed state at $E_x$=12.44 MeV but elastic scattering data imply &/Γ=62±15% for a $J^{\pi }$${=0\mathrm{}}^{+}$ level, in disagreement with the 13±2% reported by Garman et al.

Differential cross sections for proton elastic and inelastic scattering by ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$ have been measured at several proton energies between 15 and 38 MeV. Coupled channels calculations, based on multi- pole moments predicted by collective and shell-model calculations, have been performed for the g.s., $2_1^{+}$, $4_1^{+}$, $2_2^{+}$, $3_1^{+}$, $4_2^{+}$, $4_3^{+}$, and $3_1^{\mathrm{-}}$ states. Satisfactory results are obtained at all seven energies for the natural parity levels and also for the $3_1^{+}$ state when a direct $0_1^{+}$→$3_1^{+}$, ΔS=1 magnetic coupling is included.

The relative importance of the various exchange terms in the single-channel resonating group method calculations of α${+}^9$Be elastic scattering has been investigated by calculating in each case the l=0 norm kernel ranges, the l=0 to 7 phase shifts, and the differential cross sections in the c.m. incident energies in the range 0–8 MeV. A central two-nucleon interaction commonly taken in resonating group method calculations has been used, and for ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$ a cluster model wave function has been taken. The results have been compared with one another and with the experimental data at 6.06 and 7.01 MeV. It is concluded that the resonating group method in the single-channel approximation can describe reasonably well the α${+}^9$Be elastic scattering at incident energies of about 6 MeV and below. The one-nucleon exchange terms between the alpha particle and ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$ are by far the most significant, followed by those involving the exchange of the whole alpha clusters.

A procedure for embedding the boundary conditions into the solutions of three-body and four-body Schrödinger equations by using a set of homogeneous linear algebra equations is proposed.

Excitation of $1^{+}$ states in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ has been studied by 201 MeV proton inelastic scattering. Strength assigned to $1^{+}$ isovector states is found between 6.0 and 8.2 MeV excitation energy and compared with theoretical predictions. From the cross section of the recently discovered $1^{+}$ ‘‘isoscalar’’ state at 5.846 MeV, a lower limit is extracted for the volume integral of the total equivalent isoscalar spin-flip part of the nucleon-nucleon interaction.

The coupled channel method has been extended so as to include the possibilities of spherical-transitional-deformed target nuclei, different shapes for target and final nuclei, and different shapes for different reaction channels. Deformation-dependent nuclear structure wave functions, solutions of a Bohr Hamiltonian deduced from a microscopic Hamiltonian, are employed to weigh the scattering potentials for different shapes and channels. The deformation and K-dependent form factors are integrated over deformation variables and summed over K in a general theory applicable to a wide variety of targets and projectiles. Illustrative examples, including comparisons with experimental cross sections, are presented for ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ scattering from ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ and ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$, and for total neutron cross sections of ${}_{}{}^{148}{}_{}{}^{}$,150,152,154Sm.

The ${}_{}{}^{56}{}_{}{}^{}$,58Fe and the ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$(t${,}^3$He) reactions have been studied at $E_{\mathrm{t}=25\mathrm{}}$ MeV. Differential cross sections have been measured in the angular range ${\theta }_{\mathrm{lab}=5.5\mathrm{}}$°–50°. The angular distributions have been compared with coupled-channels calculations and it is shown that $J^{\pi }$ assignments can be made to a large number of states in ${}_{}{}^{56}{}_{}{}^{}$,58Mn and in ${}_{}{}^{58}{}_{}{}^{}\mathrm{Co}$. This is the first comprehensive report of the use of the (t${,}^3$He) reaction as a tool for determining such $J^{\pi }$ assignments.

Cross-section and vector-analyzing-power measurements have been carried out for ${}_{}{}^{70}{}_{}{}^{}$,72,74,76Ge(darrow ,d) at $E_{\mathrm{d}}$=8 and 16 MeV, (darrow,d’) $2^{+}$ at $E_{\mathrm{d}}$=16 MeV, and (parrow,p) and (parrow,p’${)2\mathrm{}}^{+}$ at $E_{\mathrm{p}}$=11.5 MeV. Exploratory measurements of ${}_{}{}^{70}{}_{}{}^{}$,72,74Ge(darrow,d) at $E_{\mathrm{d}}$=6 MeV have also been performed. The elastic analyzing-power data for A=70,72 are nearly identical, as are those for A=74,76, and a sudden decrease in the amplitude of $A_y$ occurs in going from A=72 to 74. The inelastic-scattering data also show near identity for the A=70,72 target nuclei as well as for A=74,76, with characteristic changes occurring between A=72 and 74. Coupled-channels calculations have been performed for all four isotopes using a macroscopic form factor employing both vibrational and rotational models. It is found that the anomalous behavior of the elastic-scattering data at $E_{\mathrm{d}}$=16 MeV and at $E_{\mathrm{p}}$=11.5 MeV is by itself not indicative of ground-state shape, but only shows the effects of target excitation on elastic scattering. The $2^{+}$ inelastic-scattering data, however, can be explained only if a vibrational model is assumed for ${}_{}{}^{70}{}_{}{}^{}$,72Ge and a prolate symmetric rotational model is assumed for ${}_{}{}^{74}{}_{}{}^{}$,76Ge. These results are indicative of a shape transition between ${}_{}{}^{72}{}_{}{}^{}\mathrm{Ge}$ and ${}_{}{}^{74}{}_{}{}^{}\mathrm{Ge}$, consistent with the conclusions drawn from transfer-reaction measurements.

The system p${+\mathrm{}}^{58}$Ni has been investigated at laboratory energies from 0.75 to 5.00 MeV. Continuous yield curves in the (p,γ) and (p,p’γ) channels were obtained with a resolution of about 2 keV. In the capture channel, 190 resonances were identified. For 56 resonances, in regions of possible analog states, γ-ray spectra were measured. Spins of 28 of the stronger resonances were determined from γ-ray angular distributions. Spins of the weaker resonances were inferred from their decay branching. Eighteen analog state candidates were identified, allowing a systematic survey of isobaric analogs up to 3 MeV in the parent ${}_{}{}^{59}{}_{}{}^{}\mathrm{Ni}$. Several of the analogs are fragmented, including the $g_{9/2}$ state at 3.550 MeV, for which a nearby companion at 3.480 MeV was found. A further ${\mathrm{}(9/2)\mathrm{}}^{+}$ resonance some 0.7 MeV below the analog state at 2.839 MeV was also found. In addition to the resonant state information, the γ decay spectra and angular distributions lead to the establishment of five new bound levels of ${}_{}{}^{59}{}_{}{}^{}\mathrm{Cu}$, at 2.993, 3.574, 3.729, 3.930, and 4.465 MeV. Nine levels, previously observed only in particle transfer reactions, at 3.309, 3.551, 3.699, 4.072, 4.207, 4.307, 4.441, 4.530, and 4.917 MeV, were seen. The decay schemes of these and of many other levels were refined.

The relative multiplicity abundance ${\mathrm{K}}^{+}$/${\mathrm{\pi }}^{+}$ and ${\mathrm{K}}^{+}$/${\mathrm{p}}^{+}$ arising in quark-gluon plasma formed in high energy nuclear collisions is determined. It is shown how these ratios assist in discriminating between various reaction channels.

High spin states in ${}_{}{}^{75}{}_{}{}^{}\mathrm{Br}$ were investigated in the reactions ${}_{}{}^{62}{}_{}{}^{}\mathrm{Ni}$${(}^{16}$O,p2n) and ${}_{}{}^{66}{}_{}{}^{}\mathrm{Zn}$${(}^{12}$C,p2n). By means of γγ- and γ-neutron multiplicity coincidence measurements, rotational bands of both parities were extended up to 7 MeV excitation energy and spin I=(33/2). The lifetimes of 17 yrast states were determined with the recoil distance and Doppler shift attenuation methods; the spin dependence of the side feeding time was also measured. The data have been analyzed in terms of the Strutinsky-Bogolyubov cranking model with a Woods-Saxon average potential. The first crossing observed in the negative parity bands is attributed to the alignment of a $g_{9/2}$ proton pair; the next irregularity which is also observed in the positive parity band is interpreted as the alignment of $g_{9/2}$ neutrons. The coexistence of prolate and oblate configurations at low spin and the change of nonaxial deformation with rotational frequency due to the polarization of the even-even core by the odd particle are discussed. The signature inversion visible in the negative parity bands as well as the changes in the signature splitting and reduction of B(E2) values at high spins may be related to a transition from γ<0° to γ>0° triaxial shapes.

The evaporation and subsequent decay of n-p states (especially ${}_{}{}^2{}_{}{}^{}\mathrm{H}_{}^{\mathrm{*}}{}_{}{}^{}$—the singlet deuteron) from compound nuclei is examined theoretically. The energy difference between a proton and neutron observed in coincidence provides information about the time interval between the thermal emission and the breakup of the n-p state. It thus offers the opportunity for measuring a lifetime of the order of ${10}^{\mathrm{-}21}$ seconds, without recourse to the relation Δt=ħ/Γ. Thermal emission of both singlet and triplet deuterons is considered. The subsequent decay through the natural mode and polarization mode is calculated. Results of Monte Carlo calculations are presented for both coincidence and singles spectra, and the feasibility of direct lifetime measurement is discussed.

Coexistence wave functions for even Ge nuclei, previously derived from fits to two-neutron transfer data, are used to calculate cross section ratios for ${}_{}{}^{\mathrm{A}\mathrm{-}4}{}_{}{}^{}\mathrm{Zn}$${(}^6$Li,d${)}^{\mathrm{A}}$Ge and ${}_{}{}^{\mathrm{A}+4\mathrm{}}{}_{}{}^{}\mathrm{Se}$(d${,}^6$Li${)}^{\mathrm{A}}$Ge.

Residues following ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$${+}^{12}$C fusion were identified by their characteristic γ rays. For several transitions in ${}_{}{}^{23}{}_{}{}^{}\mathrm{Mg}$, ${}_{}{}^{25}{}_{}{}^{}\mathrm{Mg}$, and ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$, coincident neutron spectra were measured at six angles. Through use of an evaporation code, comparisons were made of these spectra with predictions of the statistical model at five ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ projectile energies between 43.2 and 56.0 MeV. The result requires an excitation energy dependence for the effective radius parameter $r_0$, which determines the spin cutoff factor.

Reaction products arising from the interaction of ${}_{}{}^{11}{}_{}{}^{}$B${+\mathrm{}}^{12}$C and ${}_{}{}^{10}{}_{}{}^{}$B${+\mathrm{}}^{13}$C have been studied in the energy range 4<$E_{\mathrm{lab}\left(\mathrm{B}\right)<\mathrm{}9\mathrm{}}$ MeV/nucleon. From the total fusion cross sections for the two entrance channels, the critical angular momenta have been extracted and then compared as a function of compound nucleus excitation energy. Even though a limitation in the fusion cross section was observed, no common limitation was found in the critical angular momenta for these two systems up to at least a ${}_{}{}^{23}{}_{}{}^{}\mathrm{Na}$ excitation energy of 60 MeV. Above this excitation energy, the experimental uncertainties make this point less clear. Up to an excitation energy of 60 MeV in ${}_{}{}^{23}{}_{}{}^{}\mathrm{Na}$, a fusion limitation based on reaching a critical density of compound nucleus states like the yrast or ‘‘statistical’’ yrast line cannot be responsible for the fusion cross section limitations observed for these entrance channels. The present data suggest that competing entrance channel processes are responsible for the observed fusion cross section limitations.