The evaporation residue yields have been measured for the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$+${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ reaction at five bombarding energies between 62 and 150 MeV. The important contributions of the fusion channels corresponding to $3\alpha$ and $4\alpha$ emission result in a total fusion cross section which saturates at higher energies and higher absolute value than previously reported. All observations are in favor of a complete fusion mechanism up to $E\left({}_{}{}^{16}{}_{}{}^{}\mathrm{O}\right)=150\mathrm{}$ MeV.

The tensor analyzing powers of the ${}_{}{}^1{}_{}{}^{}\mathrm{H}(\overrightarrow{d},\gamma ){}_{}{}^3{}_{}{}^{}\mathrm{He}$ reaction initiated by a polarized beam are studied using the Sasakawa wave function for the three-body bound state and neglecting initial state interactions. Good agreement is obtained with recent $A_{\mathrm{yy}}$ data taken at $E_{\gamma }=14.66\mathrm{}$ MeV. It is shown that at low energy the tensor analyzing powers are sensitive to the asymptotic region of the bound state wave function and can be used to determine the asymptotic $\frac{D}{S}$ state ratio, $\eta$, in ${}_{}{}^3{}_{}{}^{}\mathrm{He}$.

Over a wide energy range, the limitation on fusion is interpreted from the properties of the compound nuclear level density obtained by taking into account the finiteness of the nucleus. The essential point is to use the shell model single particle bound states in the calculation of the grand partition function. The critical angular momentum for fusion is estimated in connection with the critical temperature for fusion.

A variational calculation of the high-spin yrast spectra in some highly neutron-rich Mo isotopes suggests the possibility of observing the backbending effect in the newly discovered region of deformation around $A=100\mathrm{}$.

Eigenfunctions for a set of coupled equations with outgoing wave boundary conditions in each channel $n$, called Weinberg states, are used to construct a separable representation of the matrix Green's functions $G_{n{n}^{\prime }}(r,r^{\prime })$. In terms of this representation, novel forms for the nonlocal optical potential in the elastic channel can be written, which take into account interchannel coupling to all orders. Expressions for the corrections to the distorted-wave Born approximation inelastic transition potentials are also given. Two expressions for the effective potential in the elastic channel are given. One involves the Weinberg eigenfunctions in the inelastic space. The other involves the Weinberg eigenfunctions for the complete (elastic plus inelastic) space. The former is more suitable for the evaluation of corrections to the distorted-wave Born approximation, the latter occurs naturally in the solution by the Sturmian method of the full set of coupled equations. Numerical approximations to the Weinberg states can be constructed by introducing auxiliary sets of Sturmian states, one set in each channel. By truncating the dimension of each set to the size $M$, one obtains separable approximations of rank $M$ to the effective potentials. The procedure involves the diagonalization of a matrix of dimension ${(M\times N)}^2$, where $N$ denotes the number of channels included in the inelastic space.

Precessions of the first $2^{+}$ and $4^{+}$ states in ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}$ have been measured employing the transient field method. The $g$ factor of the $4^{+}$ state has been deduced to be $g=0.55\mathrm{}\left(14\right)\mathrm{}$ using the known value of $g\left(2^{+}\right)$ as normalization. The obtained result agrees with the shell model prediction. The value of the transient magnetic field for Ne in Fe at $v\sim 1.5v_0$ points to a contribution of $1s$ vacancies to the transient magnetic field.

Four $M4\mathrm{}$ transitions based on the stretched particle-hole excitation ${\left(1\mathrm{}{d}_{\frac{5}{2}}1p_{\frac{3}{2}}^{-1\mathrm{}}\right)}_{4^{-}}$ have been observed in ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ by inelastic electron scattering, and their form factors have been measured over the range $q=0.8-2.8\mathrm{}$ ${\mathrm{fm}}^{-1\mathrm{}}$. The states are at 15.01 ($3^{-}$,$4^{-}$), 16.91 ($5^{-}$), 18.48 ($5^{-}$), and 20.11 MeV ($3^{-}$,$4^{-}$) and all have $T\approx 1$. The 16.91 and 18.48 MeV states together exhaust 61-84% of the possible $M4\mathrm{}$ strength for $J^{\pi }=5^{-}$, the higher percentage obtaining for a phenomenological ground-state wave function which fits the static electromagnetic moments. The 15.01 and 20.11 MeV transitions exhaust over 60% of the $M4\mathrm{}$ strength allowed for $J^{\pi }=3^{-}$, but the spins are still uncertain. Combined with recent ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}(\pi ,{\pi }^{\prime })$ results, a triplet of $5^{-}$ states with $T=0,1,0\mathrm{}$ is apparent at 14.66, 16.91, and 17.46 MeV and a three-state isospin-mixing scheme is invoked to describe the $\frac{{\pi }^{+}}{{\pi }^{-}}$ asymmetries. Using the (e,e′) data as a calibration, and assuming a simplified ground-state wave function, the joint analysis indicates the $5^{-}$ triplet exhausts roughly 60% of the isovector $5^{-}$ strength but only about 35% of the isoscalar strength. Significant $C3\mathrm{}$ strength is found in a triplet of levels at 12.82 ($4^{-}$), 11.24 ($3^{-}$), and 13.17 MeV ($2^{-}$?). The form factors are interpreted in terms of a weak coupling of the valence nucleons to a $K=3\mathrm{}$ rotational excitation of a deformed core. Finally, an isovector $M2\mathrm{}$ transition is found at 14.72 MeV ($2^{-}$?) and is analyzed in terms of a phenomenological shell-model configuration.

Stable recurrence relations, convenient for numerical calculation, are developed for Dirac-Coulomb radial integrals.

Angular distributions for the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(\mathrm{n},{\gamma }_0){}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ reaction have been measured with neutrons corresponding to excitation energies of 16.0, 19.2, 20.1, 20.8, and 21.8 MeV. Legendre polynomial coefficients have been determined to second order ($a_3$ is small). Polarized neutron measurements were obtained at excitation energies of 16.0, 18.6, 19.2, 20.1, 21.0, 21.8, and 22.3 MeV. A structure seen in the coefficient of the Legendre polynomial $P_2$ for the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(\mathrm{p},{\gamma }_0){}_{}{}^{13}{}_{}{}^{}\mathrm{N}$ reaction is also seen in the present data. A secondary doorway state at 20.5 MeV with an apparent width of 0.5 MeV is suggested by previously measured ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}(\mathrm{d},{\gamma }_0){}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ data. The presence of this state provides an explanation for the energy dependence of the cross section, the $a_2$ coefficient, and the analyzing power coefficient $b_2$ in the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(\mathrm{n},{\gamma }_0){}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ data. The same model is also able to describe the energy dependence of the cross section and the $a_2$ coefficient observed in the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(\mathrm{p},{\gamma }_0){}_{}{}^{13}{}_{}{}^{}\mathrm{N}$ reaction in the region of 16 to 22 MeV.

${}_{}{}^3{}_{}{}^{}\mathrm{He}$ charge form factors were measured by observing the scattering reaction ${}_{}{}^3{}_{}{}^{}\mathrm{He}$(e,${}_{}{}^3{}_{}{}^{}\mathrm{He}$)e from square momentum transfers 0.885 to 3.20 ${\mathrm{fm}}^{-2\mathrm{}}$. The results compare favorably with earlier electron scattering experiments. A model-independent determination of the radial charge density gives an rms radius of 1.877±0.019 fm, in excellent agreement with previous radii determinations.

Resonances at $E_{\alpha }=401,814, \mathrm{and} 953$ keV were observed in the ${}_{}{}^7{}_{}{}^{}\mathrm{Li}(\alpha ,\gamma )$ reaction. From the thick target yields the corresponding states in ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$ at 8920, 9185, and 9274 keV were found to have center-of-mass resonance strengths of 0.0088±0.0014, 0.317±0.047, and 1.72±0.17 eV, respectively. The radiative widths deduced for the latter two states are ${0.17}_{-0.03\mathrm{}}^{+0.06\mathrm{}}$ and 1.15±0.16 eV, respectively. Using a 40 mCi ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ target, $\alpha$-capture resonances were observed at $E_{\alpha }=884\mathrm{}$ (${}_{}{}^{11}{}_{}{}^{}\mathrm{C}_{}^{*}{}_{}{}^{}$ = 8105 keV) and 1376 (${}_{}{}^{11}{}_{}{}^{}\mathrm{C}_{}^{*}{}_{}{}^{}$ = 8421 keV) keV with center-of-mass resonance strengths of 0.331±0.041 and 3.80±0.57 eV, respectively. The radiative widths deduced for these states are 0.350±0.056 and 3.1±1.3 eV, respectively. The observed decay rates are compared with theoretical calculations.

We present two new nucleon-nucleon (NN) potentials: a $v_{14}$ model that is a conventional NN potential and a $v_{28}$ model with explicit $\Delta \mathrm{}\left(1232\right)\mathrm{}$ degrees of freedom. The $v_{14}$ model has 14 operator components describing NN channels, while the $v_{28}$ model has 14 additional operators, including 12 transition operators for all possible $\pi \mathrm{N}\Delta$ and $\pi \Delta \Delta$ couplings and two central operators for $\mathrm{N}\Delta$ and $\Delta \Delta$ channels; the latter are constrained so that the $v_{28}$ model has no additional free parameters for data fitting. The two models give excellent and almost identical fits to deuteron properties and np scattering below 330 MeV. The $v_{14}$ and $v_{28}$ forms are convenient for nuclear structure calculations; when many-body cluster contributions are evaluated the $v_{28}$ model will automatically include much of the effect attributed to many-body forces in conventional models, while the $v_{14}$ model will provide a standard of comparison.

An analysis is carried out of an extension of the Lee model which describes the interaction of three fermions, $V$, $N$, and $W$, with a scalar boson $\theta$ through the virtual processes $V\rightleftarrows N+\theta$ and $W\rightleftarrows V+\theta$. It is shown that the amplitudes for the physical processes $V+\theta \to V+\theta$ and $V+\theta \to N+2\mathrm{}\theta$ can be obtained from the solution of three-particle equations which differ from those of the Amado-Lovelace type as a result of the presence of the absorption channel $V+\theta \to W\to V+\theta$. The techniques used to derive the equations are not peculiar to the model, since they rely mainly on unitarity and analyticity in the subenergy and total energy variables, and hence they can be applied to realistic systems.

[NUCLEAR REACTIONS Modified three-particle equations for $V-\theta$ sector of extended Lee model.]

Differential cross sections and analyzing powers of polarized proton elastic and inelastic scattering from ${}_{}{}^{166}{}_{}{}^{}\mathrm{Er}$, ${}_{}{}^{168}{}_{}{}^{}\mathrm{Er}$, ${}_{}{}^{174}{}_{}{}^{}\mathrm{Yb}$, and ${}_{}{}^{176}{}_{}{}^{}\mathrm{Yb}$ have been measured at 65 MeV. Analysis for $J^{\pi }=0^{+}-6^{+}$ members of the ground state rotational band has been performed using coupled-channel calculations for scattering from deformed optical potentials. Excellent fits have been obtained for both cross sections and analyzing powers for $0^{+}$, $2^{+}$, and $4^{+}$ states and fairly good fits for the $6^{+}$ state. In the coupled-channel calculations, the multipole moments of each part of the deformed optical potentials were set to be equal. The quadrupole moments of the deformed optical potentials for these nuclei were found to be 4-6% larger than those of charge densities obtained by electron scattering and Coulomb excitation. A folding model calculation shows that the main part of this difference is attributed to the density dependence of the effective interaction. Mass number dependence of the phenomenological range of the effective interaction can be also reproduced from the folding calculation using the density-dependent effective interaction.

Secondary gamma rays and conversion electrons following the ${}_{}{}^{243}{}_{}{}^{}\mathrm{Am}(\mathrm{n},\gamma ){}_{}{}^{244}{}_{}{}^{}\mathrm{Am}$ reaction have been studied with crystal spectrometers and an electron spectrometer, respectively. Primary gamma rays following thermal neutron capture in ${}_{}{}^{243}{}_{}{}^{}\mathrm{Am}$ have also been measured. A level scheme of ${}_{}{}^{244}{}_{}{}^{}\mathrm{Am}$ has been constructed containing 67 excited levels. The levels are interpreted in terms of coupled proton and neutron Nilsson configurations. The results are found to be in good agreement with a semiempirical model with which excitation energies in odd-odd nuclei are calculated from those in adjacent nuclei.

A $J^{\pi }={\frac{25}{2}}^{+}$ isomer in ${}_{}{}^{205}{}_{}{}^{}\mathrm{T}1\mathrm{}$ has been observed using techniques of in-beam $\gamma$-ray spectroscopy and the ${}_{}{}^{204}{}_{}{}^{}\mathrm{Hg}(\mathrm{t},2\mathrm{}\mathrm{n}){}_{}{}^{205}{}_{}{}^{}\mathrm{T}1\mathrm{}$ reaction. The decay scheme firmly establishes the yrast levels: [$J^{\pi },E_x$ (keV)] ${\frac{11}{2}}^{-}$, 1484.02; ${\frac{15}{2}}^{-}$, 2054.57; ${\frac{17}{2}}^{-}$, 2394.18; ${\frac{19}{2}}^{-}$, 2551.56; and ${\frac{25}{2}}^{+}$, 3290.7. A candidate for a ${12}^{-}$ state in ${}_{}{}^{204}{}_{}{}^{}\mathrm{T}1\mathrm{}$ with the configuration ($\pi h_{\frac{11}{2}}^{}{}_{}{}^{-1\mathrm{}},\nu i_{\frac{13}{2}}^{}{}_{}{}^{-1\mathrm{}}$) is identified.

Proton-alpha particle coincidence spectra from 101.5 MeV ($\mathrm{p},\mathrm{p}\alpha$) reactions on ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$, ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$, ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$, ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$, ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ti}$, ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}$, and ${}_{}{}^{66}{}_{}{}^{}\mathrm{Zn}$ have been obtained in a coplanar geometry at quasifree angle pairs for each target. A missing energy resolution of $\lesssim 450$ keV was sufficient to separate the lowlying states of the residual nuclides. Data for ground-state transitions, and for eight excited states were obtained and compared with distorted-wave impulse approximation calculations. The targetmass dependence of the resultant relative ground-state spectroscopic factors is reasonably consistent with that obtained from (${}_{}{}^6{}_{}{}^{}\mathrm{Li}$,d) reactions. The corresponding absolute spectroscopic factors are larger than shell-model predictions, but sensitive to the bound-state parametrization. However, the spectral shapes do constrain the range of possible bound-state rms radii. The fits to the excited states are less satisfactory.

A new method for calculating the continuum spectrum of the direct ($a,ab$) reaction is applied to an analysis of the ${}_{}{}^{57}{}_{}{}^{}\mathrm{Ni}$(p,2p)${}_{}{}^{57}{}_{}{}^{}\mathrm{Co}$ reaction at 198 MeV. The application presented here exploits the convenient feature of the direct reaction general formalism introduced previously, which expresses the coincidence continuum cross section as a set of convolutions consisting of a doorway quasifree cross section and a number of rescattering probabilities of the quasifree particles on the residual nucleus. The method which is proposed expresses the rescattering probabilities in terms of the experimental inelastic scattering cross sections of the quasifree particles. This model successfully describes both the energy spectra and the angular distributions of the protons extracted from the measured (p,2p) two-dimensional energy spectra used for comparison.

The elastic scattering of 104 MeV $\alpha$ particles by ${}_{}{}^{40,42,43,44,48}{}_{}{}^{}\mathrm{Ca}$, ${}_{}{}^{50}{}_{}{}^{}\mathrm{Ti}$, ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}$, and ${}_{}{}^{52}{}_{}{}^{}\mathrm{Cr}$ has been analyzed by phenomenological and semimicroscopic optical potentials in order to get information on isotopic and isotonic differences of the $\alpha$ particle optical potentials and of nuclear matter densities. The phenomenological optical potentials based on a Fourier-Bessel description of the real part reveal different behavior in size and shape for the isotonic chain as compared to the isotopic chain. Odd-even effects are also indicated to be different for isotones and isotopes. The semimicroscopic analyses use a single-folding model with a density-dependent effective $\alpha \mathrm{N}$ interaction including a realistic local density approximation. The calculated potentials are fully consistent with the phenomenological ones. Isotopic and isotonic differences of the nuclear matter densities obtained from the folding model in general show a similar behavior as the optical potential differences. The results on matter densities are compared to other investigations.

The energy spectra of neutrons and photons emitted by thick targets of carbon, iron, copper, and lead at angles of 0, 15, 30, 45, 75, and 135 deg to the incident beam of 33-MeV deuteron, 65-MeV ${}_{}{}^3{}_{}{}^{}\mathrm{He}$, and 65-MeV alpha ions were obtained by unfolding the pulse height distributions measured with an NE-213 scintillator. The angular distributions of neutrons above 4 MeV and photons above 1.5 MeV were obtained by integrating the measured spectra. The total neutron yield was obtained by estimating the neutron yield below a few MeV by fitting the spectra measured above that energy to the Maxwellian distribution and showed good agreement with other experimental results. The measured spectra were analyzed by the thick-target radiation transport Monte Carlo code based on the intranuclear-cascade-evaporation model. The validity of the model was tested at the lower projectile energy limit through this comparison.