The energy spectra and yields of particles of $3<~Z<~8$ emitted in the spontaneous fission of ${\mathrm{Cf}}^{252}$ were measured. The experiment was carried out using a particle telescope consisting of two $\frac{\mathrm{dE}}{\mathrm{dx}}$ gas-filled proportional counters and a solid-state $E$ counter. The cutoff energies were relatively low since essentially no absorber foil was placed between source and detector. The yields per ${10}^3$ fission $\alpha$ particles are: Li, 2.9 ± 0.5; Be, 6.5 ± 0.7; B, 0.35 ± 0.10; C, 4.3 ± 0.9; N, ≥ 0.66 ± 0.15; O, ≥ 0.05 ± 0.01. Trajectory calculations were carried out for Li, Be, and C, and the initial conditions which give best agreement with the experimental results were obtained.

The Mössbauer resonance in ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$ has been observed for a source of dilute Pt in Fe at temperatures between 0.06 and 20 K, obtained by employing a ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ dilution refrigerator for cooling. At these low temperatures, the source nuclei are partially oriented because of the magnetic hyperfine interaction present in the alloy. The intensities of the observed hyperfine lines allow the determination of the polarization of the 77-keV first excited state in ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$, which is populated by $\beta$ decay from the ${}_{}{}^{197}{}_{}{}^{}\mathrm{Pt}$ source. From this polarization, one can calculate the mixing ratio of the squares of the reduced matrix elements of different tensor rank present in the $\beta$ transition. For the first-forbidden $\beta$ decay of ${}_{}{}^{197}{}_{}{}^{}\mathrm{Pt}$ ($\Delta I=0\mathrm{}$, $\Delta \pi =-1\mathrm{}$), we find the mixing ratio of rank-one elements to the rank-zero elements to be ${\beta }^2=7\mathrm{}\pm 1$.

In order to search for new neutron-deficient isotopes of uranium and thorium, targets of ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ were bombarded with beams of ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}$, ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$, ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$, and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ in the Berkeley HILAC. The reaction products were transported from the reaction cell by the helium-jet technique and their $\alpha$-disintegration characteristics measured by on-line techniques of $\alpha$ spectroscopy. Energy values, excitation functions, and half-lives of $\alpha$-particle groups were measured. Only fragmentary evidence for uranium nuclei was found, because of intense losses by nuclear fission, but definite proof was obtained for the previously unknown millisecond isotopes ${}_{}{}^{222}{}_{}{}^{}\mathrm{Th}$ and ${}_{}{}^{221}{}_{}{}^{}\mathrm{Th}$, and for their decay products ${}_{}{}^{218}{}_{}{}^{}\mathrm{Ra}$, ${}_{}{}^{214}{}_{}{}^{}\mathrm{Rn}$, ${}_{}{}^{217}{}_{}{}^{}\mathrm{Ra}$, and ${}_{}{}^{213}{}_{}{}^{}\mathrm{Rn}$. Improvements were made on the literature values for ${}_{}{}^{223}{}_{}{}^{}\mathrm{Th}$ and its decay products.

The new $\alpha$ data help greatly in the determination of the trends in $\alpha$-decay energies for isotopes of even-$Z$ elements, particularly in the poorly defined region just above the 126 neutron shell. This allows the preparation of a more reliable set of predictions for many unknown nuclei.

The ($d, t$) reactions on ${\mathrm{Mo}}^{94}$, ${\mathrm{Mo}}^{96}$, and ${\mathrm{Mo}}^{100}$ were studied with 17-MeV incident deuterons. The experimental angular distributions of the triton groups were compared with distorted-wave Born-approximation (DWBA) calculations to determine the $l$ values and the spectroscopic factors. The $I^{\pi }$ and excitation energy of the levels found in this study are compared with those from ($d, p$) reactions leading to the same final states. The occupation numbers and single quasiparticle energies are calculated and compared with previous results.

The shifts of single-particle energy levels caused by distortions of nuclear equipotential surfaces is examined. Application of this approach is made to neutron single-particle states in the heavy-element region. Typical single-particle energy shifts are displayed in figures.

The equipotential shapes studied in this paper are axially symmetric and were obtained by the replacement ${{\omega }_0}^2{\mathcal{r}}^2\to {{\omega }_{\rho }}^2{\rho }^2+{{\omega }_z}^2{z}^2+{{\omega }_0}^2({\rho }^2+z^2)G\left(z^2\right)$ with $G\left(z^2\right)$ of the form $G\left(z^2\right)=e^{-A{Z}^2}\Sigma \stackrel{}{n}{B}_n{\left(z^{2t}\right)}^n$

A Woods-Saxon well was used for the central field, and eigenstates of the cylindrical harmonic oscillator ($|n_{\perp }, \lambda , n_Z〉$) were used as a basis set in these calculations. ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$ is analyzed in detail.

Excitation functions for proton elastic and inelastic scattering from ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$, studied from 2.0- to 6.0-MeV bombarding energy and for various scattering angles, revealed structure which was ascribed to isobaric analog resonances of the nucleus ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$. The conjecture that these resonances may have a significant influence on the spin-flip probability observed in inelastic scattering was tested by varying the transmission coefficients in a Hauser-Feshbach calculation. It was found that this effect can give rise to an enhancement of the calculated spin-flip probability consistent with previous measurements.

The recently discovered second diffraction minimum in the elastic form factor of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, alternatively described by a harmonic-oscillator model containing pair correlations or by an independent-particle model with a finite Woods-Saxon well, can also be obtained by the much simpler $\alpha$-particle model.

Cross sections for complete fusion of ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}$, ${}_{}{}^{86}{}_{}{}^{}\mathrm{Kr}$, and ${}_{}{}^{136}{}_{}{}^{}\mathrm{Xe}$ projectiles with various targets are calculated as a function of the mass of the compound nucleus formed. Maximum completefusion cross sections of 200-300 mb are indicated for production of excited nuclei with $A\simeq 300$.

Differential cross sections for the elastic scattering of ${\mathrm{He}}^3$ by ${\mathrm{He}}^4$ have been measured from 21.9 to 155.0° (c.m.) at ${\mathrm{He}}^3$ energies of 17.79, 19.99, 22.00, 23.98, 26.00, 28.00, and 30.00 MeV (lab). The relative standard deviations of the data are typically less than 2.5%, but become larger at angles where the cross section is very low. In addition to relative errors, the over-all error includes a standard deviation of 3% in the cross-section scale. The measurements are compared with theoretical calculations using the resonating-group method in the one-channel approximation. Differences between theory and experiment can be qualitatively understood as being caused mainly by the omission of reaction channels in the theory.

Differential cross sections for ${\mathrm{He}}^3$ + ${\mathrm{He}}^3$ elastic scattering have been measured at 18 angles from 12.5 to 45° (lab) at energies of 17.91, 20.00, 22.00, 24.00, 26.00, 28.00, and 30.00 MeV (lab). In addition, differential cross sections have been measured at intermediate energies from 19.00 to 32.00 MeV (lab) at angles of 20, 28, 36, and 45° (lab). The relative standard deviations of the data are generally less than 2%, and there is an additional standard deviation in the cross-section scale of 3%. The measurements are compared with theoretical calculations using the resonating-group method in the one-channel approximation. A broad resonance in the $l=3\mathrm{}$ partial wave is predicted by the theory, and such a resonance has been observed in the present experiment. Differences between theory and experiment can be qualitatively understood as being caused principally by omission in the theory of reaction channels and noncentral forces. The effect of radial distortion in resonating-group calculations for the ${\mathrm{He}}^3$ + ${\mathrm{He}}^3$ system has also been investigated in an approximate manner. It is found that the effect can be quite significant for calculations of the energies of states in ${\mathrm{Be}}^6$ below the ${\mathrm{He}}^3$ + ${\mathrm{He}}^3$ threshold.

The Faddeev formalism is used to compute the ground-state energy of the triton for a simple model in which the nucleon-nucleon force is given by a spin-independent $s$-wave Herzfeld potential (hard core with outside square well). The effective nucleon-nucleon potential used corresponds to the usual weighted average of triplet and singlet potential strengths. The two-variable Faddeev equation is solved using the complete off-shell $t$ matrix given by: (1) an exact analytic expression, and (2) an integral-equation formalism recently proposed. Three-body calculations based on both evaluations of the two-body $t$ matrix lead to a triton binding energy of 8.13 MeV with about 0.5% accuracy.

The effect of strong final-state interactions on the process $A(e, e^{\prime } p)B$ is investigated. Cross sections for this process are calculated for various bound-state proton wave functions, and an optical-model potential is used to describe the final-state interaction.

An approximation made in previous Brueckner-Hartree-Fock calculations is removed. Both the hole-hole and the particle-hole matrix elements of the single-nucleon potential are now calculated with the correct available energy of the pair. It is shown that, with a given $G$ matrix, the occupied states and energies do not depend on the prescription used for the particle-particle elements. The formalism is easily extended to include Brandow's occupation probabilities.

A method is developed for evaluating self-consistent occupation probabilities in Brueckner-Hartree-Fock calculations of finite nuclei. The method does not involve explicitly the overlaps of defect wave functions but is based instead on the energy dependence of the $G$ matrix elements. Results are presented for ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ using a $G$ matrix which shifts only the low-lying intermediate-particle spectrum.

It is shown how one can use the results of a nuclear-structure calculation in the theory of nucleon-nucleus scattering. We restrict ourselves to the simple case of nucleon scattering on a hole nucleus. The correlations of the ground state have been included.

The high-energy elastic scattering of nucleons by nuclei is studied using the optical-potential operator provided by Watson's multiple-scattering theory. The main motivation is to investigate the possibility of detecting two-body correlations in terms of an optical potential. We have obtained an expression for the second-order potential in coordinate space which explicitly exhibits its nonlocality in terms of the two-body correlations arising from the Pauli principle and the repulsive core of the nucleon-nucleon interaction. We have performed a self-consistent analysis of the elastic scattering of 1-GeV protons on ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ using a reasonable nucleon-nucleon scattering amplitude, the one-body density obtained from elastic electron scattering, and a parametrization for the two-body density consistent with the one-body density and dependent upon a parameter identifiable as a correlation length. We have also attempted to discriminate among several sets of nucleon-nucleon phase shifts at 630 MeV. The scattering of 1-GeV protons by ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ is studied in order to investigate the relative importance of Pauli and short-range correlations. We also critically compare our work with that of several others.

We introduce a new separable expansion for local potentials. The expansion, called the unitary pole expansion, has real, energy-independent form factors, and satisfies the requirements of two-particle unitarity in all orders. The convergence of the expansion is investigated by comparing expanded and exact $T$ matrices for negative energies, and by performing three-body bound-state calculations. In the latter case, a one-term approximation gives energies accurate to within 2% for potentials containing repulsion of the magnitude indicated by two-nucleon data.

An attempt is made to improve the predictions of the $A$ dependence of giant dipole energies of the two-fluid hydrodynamical models by the introduction of a more realistic surface behavior of the ground-state densities. The Euler-Lagrange equations of motion for the dipole oscillation are obtained by the expansion of the energy functional $\epsilon [\rho , {\left(\overrightarrow{\nabla }\rho \right)}^2, \alpha (\overrightarrow{\mathrm{r}}\left)\right]$, where minimization yields acceptable neutron and proton densities, in quadratic powers of the densities and their derivatives. The equations are solved under certain limiting conditions, but within these limitations a much better $A$ dependence is obtained.