The angular distributions of the elastic and inelastic cross sections for ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$+${}_{}{}^9{}_{}{}^{}\mathrm{Be}$ have been measured at laboratory energies of $E\left({}_{}{}^9{}_{}{}^{}\mathrm{Be}\right)=35, 40, 45, \mathrm{and} 50$ MeV. Double folding and optical model calculations were carried out in order to fit the elastic scattering while the inelastic scattering cross sections were analyzed using the coupled-channels procedure. The renormalization factor of the real double folded potential was found to decrease as energy increased in order to obtain any successful fit. In the optical model analysis, good fits were obtained using the same set of optical parameters at all energies except at backward angles, where at higher energies better fits were obtained with a shallower attractive potential. In the coupled-channels analysis, good fits were obtained using an optical model with a deep real well. The potential deformation was found to be $\beta =0.36\mathrm{}$.

Levels of the ground-state cascade of ${}_{}{}^{98}{}_{}{}^{}\mathrm{Pd}$ up to $J^{\pi }={16}^{+}$ were established by means of the reaction ${}_{}{}^{70}{}_{}{}^{}\mathrm{Ge}({}_{}{}^{32}{}_{}{}^{}\mathrm{S},2\mathrm{p}2\mathrm{n}\gamma ){}_{}{}^{98}{}_{}{}^{}\mathrm{Pd}$ with $E_{\mathrm{lab}}=120\mathrm{}$ MeV. The ${}_{}{}^{96}{}_{}{}^{}\mathrm{Ru}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$,${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$)${}_{}{}^{98}{}_{}{}^{}\mathrm{Pd}$ reaction was used to aid in the nuclidic identification of the observed $\gamma$-ray transitions. We compare the excitation energies of the new states of ${}_{}{}^{98}{}_{}{}^{}\mathrm{Pd}$ with states of the $N=52\mathrm{}$ isotone ${}_{}{}^{96}{}_{}{}^{}\mathrm{Ru}$, which were populated using four distinct reactions. No evidence has been found for the existence of collective four-particle—two-hole states involving the excitation of a pair of $g_{\frac{9}{2}}$ neutrons across the $N=50\mathrm{}$ shell closure. The level schemes are discussed in terms of the nuclear shell model while the empirical ratios of energies are presented from the viewpoint of the variable moment of inertia model.

A target of ${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}$ has been bombarded with 114 MeV and ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}$ and with 114 MeV and 129 MeV ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ beams. Recoiling reaction products were chemically isolated and the cross sections for protactinium, uranium, and neptunium isotopes were determined. The width of the cross section distributions for a given $Z$ and their neutron-richness are the same as those for similar transfers in Ne+${}_{}{}^{248}{}_{}{}^{}\mathrm{Cm}$ reactions. Population of low spin isomeric states is favored in these reactions over population of high spin states. As was seen in reactions with heavier targets, an increase in reaction energy does little to shift the evaporation residues toward neutron deficiency. The implications are that only primary products with little or no excitation energy and angular momentum survive the fission process to become evaporation residues in these systems, and that the production of these nuclides is more controlled by the change in the identity of the projectile than by the corresponding change in the target.

New elastic scattering angular distributions extending over the large angular range 10°—170° c.m. are reported for ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$+${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ at 24 and 30 MeV, ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$+${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ at 25.7 MeV, and ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$+${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ at 34 MeV. These data have been analyzed and are well described by the optical model using Woods-Saxon potentials, or by potentials with a double-folded real part. Using these and previously published data, average energy-dependent potentials have been obtained. Improved descriptions of the elastic scattering of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$+${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$+${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, and ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$+${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ for energies from the Coulomb barrier up to 26 MeV/nucleon are obtained with these new average potentials compared with existing ones.

A differentially pumped gas cell was used to study the angular and energy dependence of elastic and inelastic scattering of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ from ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$. The data exhibit the characteristic features of gross and intermediate structures observed previously for lighter systems. The slopes of the measured angular distributions show rapid variations as a function of energy and a strong rise toward backward angles. The data are discussed in terms of $\alpha$-particle exchange, resonances, and statistical fluctuations.

The mass-yield distribution from the fission of ${}_{}{}^{242}{}_{}{}^{}\mathrm{Pu}$ induced by 15.1-MeV neutrons was measured. Yields were measured for 65 fission products from ${}_{}{}^{85}{}_{}{}^{}\mathrm{Kr}$ to ${}_{}{}^{151}{}_{}{}^{}\mathrm{Pm}$. From these data the total chain yields for 43 mass numbers were obtained and the mass-yield curve constructed. Fission product activities were measured by Ge(Li) $\gamma$-ray spectrometry of the irradiated ${}_{}{}^{242}{}_{}{}^{}\mathrm{Pu}$ target and by chemical separation of the fission product elements Pd, Ag, Cd, Sn, Sb, and Ce followed by $\beta$ counting or $\gamma$-ray spectrometry. The peak-to-valley ratio in the mass-yield distribution is about 9.5. The average masses of the light and heavy groups are 101.5 and 136.5, respectively.

A simple procedure is described for determining the structure of hypernuclei. This procedure allows for complete flexibility in the hyperon wave function, while eliminating spurious center of mass components. The method is applied to ${}_{\Lambda }{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{\Lambda }{}^7{}_{}{}^{}\mathrm{L}$, and ${}_{\Lambda }{}^{16}{}_{}{}^{}\mathrm{O}$. Center of mass corrections are large for the ${}_{\Lambda }{}^6{}_{}{}^{}\mathrm{Li}$ and ${}_{\Lambda }{}^7{}_{}{}^{}\mathrm{Li}$ $p$ states and still substantial for ${}_{\Lambda }{}^{16}{}_{}{}^{}\mathrm{O}$. Spectra and selected transition and formation rates are calculated. Comparison is made with the recently measured ${\frac{5}{2}}^{+}\to {\frac{1}{2}}^{+}$ gamma-ray energy in ${}_{\Lambda }{}^7{}_{}{}^{}\mathrm{Li}$. Large changes are seen in the $l_{\Lambda }=1\mathrm{}$ wave functions between ${}_{\Lambda }{}^6{}_{}{}^{}\mathrm{Li}$ and ${}_{\Lambda }{}^{16}{}_{}{}^{}\mathrm{O}$. The $l_{\Lambda }=1\mathrm{}$ levels inferred from (${\mathrm{K}}^{-}$,${\pi }^{-}$) are well reproduced. The ground state ${}_{\Lambda }{}^{16}{}_{}{}^{}\mathrm{O}$ is overbound, suggesting that a two-body $\Lambda \mathrm{N}$ interaction must be modified in the nuclear interior.

The (${\pi }^{+}$,${\pi }^0$) and (${\pi }^{-}$,${\pi }^0$) reactions were studied on a variety of nuclei at a bombarding energy of 160 MeV. The full ${\pi }^0$ energy spectra were measured with a ${\pi }^0$ spectrometer at several detection angles. The energy spectra and angular distributions are characteristic of quasifree reactions. Effects due to multiple scattering, neutron screening, and Pauli blocking are clearly observed.

The inelastic scattering of 162 MeV ${\pi }^{+}$ and ${\pi }^{-}$ to $8^{-}$ states in ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}$ was studied. Isoscalar and isovector structure amplitudes were extracted for each state. The summed isoscalar strength corresponds to only 11% of that predicted in an ${\left[{\left(f_{\frac{7}{2}}\right)}^{-3\mathrm{}}{g}_{\frac{9}{2}}\right]}_{8^{-}}$ calculation, while 38% of the isovector strength is observed. This is similar to the quenching of strength observed in lighter nuclei and demonstrates that the strong quenching of the isoscalar spin-flip strength persists in the $f-p$ shell.

The ${}_{}{}^{14}{}_{}{}^{}\mathrm{Be}$ nucleus has been produced in the reaction ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}({\pi }^{-},{\pi }^{+})$. The cross section for the reaction is roughly that which would be expected from the $A^{-\frac{4}{3}}$ mass dependence observed for nonanalog (${\pi }^{+}$,${\pi }^{-}$) reactions on self-conjugate nuclei. If it is the ground state that we observe, the mass excess of ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ is ∼600 keV smaller (more bound) than expected from systematics.

We present measurements of the nonanalog pion double charge exchange reaction, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}({\pi }^{-},{\pi }^{+}){}_{}{}^{18}{}_{}{}^{}\mathrm{C}(\mathrm{g}.\mathrm{s}.\mathrm{})$, a transition between a $T=1\mathrm{}$ state and a $T=3\mathrm{}$ state, and compare the results to earlier measurements on self-conjugate targets.

Six-quark probabilities for the $\Lambda \mathrm{N}$ and $\Sigma \mathrm{N}$ scattering systems are calculated in the hybrid quark model. A coupled-channel treatment based on modified Nijmegan potentials is carried out in the external region. Implications for a possible dibaryon in the $\Lambda \mathrm{N}$ system are discussed.

Data by Altman et al. for exclusive pion absorption on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ are reexamined using an impulse approximation formalism which treats pion absorption as proceeding only through absorption on a deuteronlike structure within the target nucleus. The results indicate that previous estimates of the strength of this quasi-deuteron absorption component of the reaction mechanism by Altman et al. are probably too low. Reasonable agreement with the shape and magnitude of the observed angular distribution is achieved by ignoring distortions for both the incoming pion and outgoing nucleons, with somewhat poorer agreement with inclusion of distortions.

New measurements of ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$,${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}({\pi }^{+},{\pi }^{-})$ differential cross sections are reported and compared to previous differential cross sections for double charge exchange on $T\ge 1$ nuclei.

The vector analyzing power $i{T}_{11}$ has been measured for the $\pi \mathrm{d}\to 2\mathrm{p}$ reaction at seven incident pion energies between 112 and 325 MeV, using a vector polarized deuteron target. The results cover an average of 12 angles per incident pion energy. A comparison with existing theoretical calculations is made. The value of these data with respect to ongoing phase shift analyses of the $\mathrm{pp}\to \pi \mathrm{d}$ reaction is discussed.

The photoproduction of charged pions from light nuclei is investigated in a distorted wave impulse approximation carried out in momentum space. This permits a straightforward inclusion of nonlocal terms in the pion production operator such as that of Blomqvist and Laget. The interaction of the outgoing pion with the residual nuclear state is described by the optical potential of Stricker, McManus, and Carr. The cross section for pion production from $p$-shell nuclei is decomposed into partial cross sections labeled by transition angular momenta and spin which are almost independent of nuclear structure. Using the reaction ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}(\gamma ,{\pi }^{-}){}_{}{}^{13}{}_{}{}^{}\mathrm{N}_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{}{}_{}{}^{}$, the effects of the delta isobar in the production operator on these partial cross sections is investigated. The same reaction is used to demonstrate the inadequacy of local coordinate space analyses.

Radiative proton capture reactions into nuclei with closed subshells and into the neighboring nuclei with one additional proton produce gamma-ray spectra with remarkably similar major features. Detailed measurements of ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}(\mathrm{p},\gamma ){}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(\mathrm{p},\gamma ){}_{}{}^{13}{}_{}{}^{}\mathrm{N}$, described here, reveal additional striking similarities. A generalized direct-semidirect picture of the reaction is presented, from which quantitative relationships between such capture reaction pairs may be derived, including comparisons of angular distributions, analyzing powers, and cross-section ratios over a wide range of bombarding energies. The data are in good agreement with the theoretical predictions.

The semiclassical and quantal inversion problems at fixed energy are solved for a number of nuclear scattering systems at various energies. The scattering function is represented as a particular rational or nonrational function of angular momentum. At low energies the semiclassical inversion generally breaks down; it works, however, surprisingly well in many cases.

The deuteron photodisintegration with forwardgoing proton is calculated using a new formalism for organizing matrix elements. Relativistic effects are thoroughly discussed. Different ways of calculating retarded electric multipoles are investigated. Meson exchange currents are included in various approximations. The spin-orbit dipole operator is found to dominate the relativistic corrections.

We consider the elastic scattering of nucleons from spin ½ targets via parity-mixed resonances and derive expressions for the longitudinal parity nonconserving analyzing power. We neglect any direct parity nonconserving processes—the parity nonconservation being assumed to be due solely to the resonances. We then consider a particularly interesting example—the scattering of protons by ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ over $0^{+}$ and $0^{-}$ $I=1\mathrm{}$ resonances. We show that in this case longitudinal analyzing power measurements yield, with little theoretical uncertainty, the parity nonconserving matrix element between the $0^{+}$ and $0^{-}$ levels. The large width of the $0^{-}\left(2\mathrm{}{s}_{\frac{1}{2}}\right)$ resonance compared to that of the $0^{+}\left(1\mathrm{}{p}_{\frac{1}{2}}\right)$ resonance produces a significant enhancement of the predicted effect. Because of the large size of elastic scattering cross sections a longitudinal analyzing power experiment can achieve small statistical errors. The ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ resonances are especially interesting because the mixing is essentially pure $\Delta I=0\mathrm{}$.