The giant resonance region of ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$ has been investigated by means of inelastic electron scattering in a momentum transfer range 0.36-1.25 ${\mathrm{fm}}^{-1\mathrm{}}$. The data show a splitting of the dipole resonance into two main peaks at 22 and 25.5 MeV, with some structure around 20 MeV and strength extending down to 13 MeV. The structure from 19 to 30 MeV correlates well with radiative capture and photodisintegration data and is in qualitative agreement with shell model predictions of the isospin splitting of the giant dipole resonance. The data show considerable spin-flip $E1\mathrm{}$ strength, which agrees well with the predictions of the generalized Goldhaber-Teller model. Additional structure found in the energy region from ∼ 14 to ∼ 19 MeV has been analyzed as a $C2-C1\mathrm{}$ superposition. The $C2\mathrm{}$ strength in the 14-18.5 MeV region exhausts up to 22% of the isoscalar energy-weighted sum rule (Helm model, $J=\frac{3}{2}$ assumed). The amount of $C2\mathrm{}$ strength in the region from 18.5 to 30 MeV is negligible.

NUCLEAR REACTIONS ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}(e, e^{\prime })$, $E=52-193.5\mathrm{}$ MeV, $\theta =48\mathrm{}°-141\mathrm{}°$. Enriched gas target. Measured $\sigma (E^{\prime }, \theta )$. Deduced giant resonances differential form factors. Deduced $C1\mathrm{}$, $C2\mathrm{}$ strength distributions with Helm model. Compared differential $C1\mathrm{}$ form factor to shell model calculations. Compared $C2\mathrm{}$ strength to energy-weighted sum rule. Compared $E1\mathrm{}$ strength to generalized Goldhaber-Teller model.

In the study of pion interactions with the nucleus one requires an off-shell model of the pion-nucleon scattering amplitude. It is desirable to have an amplitude that is not only correct on shell, but also has reasonable off-shell properties. In this work we introduce an off-shell model of the $\pi -N$ $T$ matrix that is composed of two parts. The first part has the correct $s$ and $u$ channel nucleon poles and the second part is represented by a separable form. The model provides a good fit to the on-shell data up to $\surd s\simeq 1300$ MeV and provides a satisfactory representation of the off-shell behavior in the region ${M_N}^2<s<\mathrm{}{(M_N+3\mathrm{}{m}_{\pi })}^2$. This range includes a subthreshold region which is important for the description of low-energy pion-nucleus scattering.

NUCLEAR REACTIONS Pion-nucleon scattering amplitude, off-shell models.

Differential cross sections have been measured for the ${}_{}{}^{30}{}_{}{}^{}\mathrm{Si}(p, \alpha ){}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ reaction at an incident energy of 40.75 MeV. The experimental ($p, \alpha$) relative cross sections are well reproduced by distorted wave direct pickup calculations with a triton cluster form factor and current shell model wave functions.

NUCLEAR REACTIONS ${}_{}{}^{30}{}_{}{}^{}\mathrm{Si}(p, \alpha ){}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, $E_p=40.75\mathrm{}$ MeV; measured $\sigma (E_x, \theta )$; studied reaction mechanism; enriched target. DWBA analysis.

Elastic scattering angular distributions were measured for 46-MeV ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ over the ∼ 30°-110° range and for 41-MeV $\alpha$ particles over the ∼ 25°-150° range for the neighboring targets ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{28,29,30}{}_{}{}^{}\mathrm{Si}$. For $\alpha$ particles, $l=2\mathrm{}$ inelastic scattering data were also obtained at angles beyond ∼ 50°. For ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ the three Si targets yield similar angular distributions that are different from that of ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ at angles larger than ∼ 55°. The elastic $\alpha$-particle data supplement earlier back angle data to yield almost complete angular distributions. The ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ $\alpha$-particle elastic angular distribution exhibits an anamoly in the 80°-150° region. The ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ data were fitted by optical model potentials with either volume or surface absorption. To fit all of the $\alpha$-particle elastic scattering data, potentials with both volume and surface absorption, with separate geometry parameters, were needed. Distorted-wave Born-approximation analyses of the $\alpha$-particle inelastic scattering data yield values of ${\beta }_2$ that are in reasonable agreement with values obtained from analyses of scattering at other energies and incident particles.

NUCLEAR REACTIONS (${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$) at MeV and ($\alpha , {\alpha }^{\prime }$) at 41 MeV from, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{28,29,30,}{}_{}{}^{}\mathrm{Si}$; enriched targets. Measured $\sigma \left(\theta \right)$; performed optical model and DWBA analyses; deduced scattering potentials and ${\beta }_2$ values.

An optical potential appropriate to elastic scattering of neutrons by oxygen is calculated with the starting point being the basic nucleon-nucleon interaction. A soft core force is employed so that matrix elements are finite and perturbation expansions are (apparently) convergent. All terms up to second order in the interaction are retained including correlation effects previously ignored. The calculations are carried out in a space large enough to minimize truncation effects. The resulting nonlocal energy dependent complex optical potential is used to calculate low energy $s$-wave phase shifts. These are compared with the results generated by an empirically fitted optical potential and with the results of previous calculations. The scattering length and effective range parameter are also calculated. Given the nature of the calculation, the results are quite encouraging.

NUCLEAR REACTIONS $n$-${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, optical potential, approximate many-body scattering theory.

Partial-wave dispersion relations are presented which describe both 2 → 2 bound-state amplitudes, 2 → 3 breakup amplitudes, and 3 → 3 three-particle scattering amplitudes. The dispersion relations are reduced to one-dimensional integral equations by absorbing the momentum dependence of the 2 → 3 and 3 → 3 amplitudes in the three-body phase-space factors. The momentum dependence is obtained by solving final-state unitarity equations. For $S$-wave nucleon-deuteron scattering the nature of this off-shell dependence is described in detail. Dynamical singularities of the amplitudes which occur in the dispersion relations are discussed, and the modifications of the dispersion relations due to the presence of anomalous thresholds are written out explicitly. The physical importance of three-body unitarity for the bound-state properties of three-body systems is reviewed and possible applications of the present theory to few-nucleon and pionic systems are briefly discussed.

NUCLEAR REACTIONS Three-body equations. Partial-wave dispersion relations. Three-body unitarity. Final-state unitarity and zero-range approximations. Nucleon-deuteron scattering and breakup.

The ($p, p^{\prime }\gamma$) reaction is used to investigate the structure of the low lying states of ${}_{}{}^{69}{}_{}{}^{}\mathrm{Ga}$. Measured angular distributions, level cross section, and centroid shifts allow spin, parity, and mean life assignments to be made to several excited states. The experimental results are compared with the theoretical three particle cluster-core coupling model.

NUCLEAR REACTIONS ${}_{}{}^{69}{}_{}{}^{}\mathrm{Ga}(p, p^{\prime }\gamma )$, $E_p=3.0-5.1\mathrm{}$ MeV, enriched targets. Measured $E_{\gamma }$, $I_{\gamma }$, $I_{\gamma }\left(\vartheta \right)$, ${\sigma }_{\gamma }$, $\Delta E_{\gamma }\left(\tau \right)$ deduced ${}_{}{}^{69}{}_{}{}^{}\mathrm{Ga}$ levels, branching ratios, $\tau$, $\delta \left(\frac{E2\mathrm{}}{M1\mathrm{}}\right)$, $B\left(E2\mathrm{}\right)\mathrm{}$ $B\left(M1\mathrm{}\right)\mathrm{}$; Ge(Li) detectors.

The $B(E2;I_{\mathrm{g}.\mathrm{s}.\mathrm{}}\to I_{\mathrm{g}.\mathrm{s}.\mathrm{}}+1)$ and $B(E2;I_{\mathrm{g}.\mathrm{s}.\mathrm{}}\to I_{\mathrm{g}.\mathrm{s}.\mathrm{}}+2)$ were determined for the isotopes ${}_{}{}^{155}{}_{}{}^{}\mathrm{Gd}$, ${}_{}{}^{161,163}{}_{}{}^{}\mathrm{Dy}$, ${}_{}{}^{167}{}_{}{}^{}\mathrm{Er}$, and ${}_{}{}^{175}{}_{}{}^{}\mathrm{Lu}$ by means of Coulomb excitation with $\alpha$ particles. Elastically and inelastically scattered $\alpha$ particles were detected either with a magnetic spectrograph or with surface barrier detectors. The measurements were performed in the energy range from 9.0 to 13.5 MeV. The results are compared with other older measurements and are discussed in terms of the rigid rotor model.

NUCLEAR REACTIONS ${}_{}{}^{155}{}_{}{}^{}\mathrm{Gd}$, ${}_{}{}^{161,163}{}_{}{}^{}\mathrm{Dy}$, ${}_{}{}^{167}{}_{}{}^{}\mathrm{Er}$, ${}_{}{}^{175}{}_{}{}^{}\mathrm{Lu}$ ($\alpha , {\alpha }^{\prime }$). $E=9.0\mathrm{} \mathrm{to} 13.5$ MeV measured $\frac{d{\sigma }_{\mathrm{el}}}{d{\sigma }_{\mathrm{inel}}}$. Deduced $B\mathrm{}\left(E2\mathrm{}\right)\mathrm{}$ values, $Q_0$, validity of rigid rotor model.

The ${}_{}{}^{234}{}_{}{}^{}\mathrm{U}({}_{}{}^3{}_{}{}^{}\mathrm{He}, d){}_{}{}^{235}{}_{}{}^{}\mathrm{Np}$ and ${}_{}{}^{234}{}_{}{}^{}\mathrm{U}(\alpha , t){}_{}{}^{235}{}_{}{}^{}\mathrm{Np}$ proton-transfer reactions were studied using 30-MeV ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ beams. Information is obtained for the following configurations: $\frac{5}{2^{+}}\left[642\mathrm{}\uparrow \right]$, $\frac{5}{2^{-}}\left[523\mathrm{}\downarrow \right]$, $\frac{1}{2^{-}}\left[530\mathrm{}\uparrow \right]$, and $\frac{3}{2^{-}}\left[521\mathrm{}\uparrow \right]$. Experimental cross sections are compared to theoretical values calculated including Coriolis and $\Delta N=2\mathrm{}$ mixing. Nilsson band assignments are made on the basis of cross section patterns as well as the ratio of the cross sections for the two reactions.

NUCLEAR REACTIONS ${}_{}{}^{234}{}_{}{}^{}\mathrm{U}({}_{}{}^3{}_{}{}^{}\mathrm{He}, d)$, ${}_{}{}^{234}{}_{}{}^{}\mathrm{U}(\alpha , t)$, $E=30\mathrm{}$ MeV; measured $E_x$, $\sigma \left(\theta \right)$. ${}_{}{}^{235}{}_{}{}^{}\mathrm{Np}$ deduced levels. Enriched target. Nilsson configurations.

Levels in ${}_{}{}^{154}{}_{}{}^{}\mathrm{Gd}$ have been studied using the ${}_{}{}^{152}{}_{}{}^{}\mathrm{Sm}(\alpha , 2n\gamma )$ reaction at an energy of 24 MeV. Singles spectra, $\gamma -\gamma$ coincidence spectra, and angular distributions were obtained in-beam using Ge(Li) detectors. Among the new levels proposed in ${}_{}{}^{154}{}_{}{}^{}\mathrm{Gd}$ are as follows: a $7^{+}$ state in the $\gamma$ band; $7^{-}$, $9^{-}$, and ${11}^{-}$ states in an odd-spin octupole-vibrational band based at 1241 keV; possible $7^{+}$ and $8^{+}$ states in the $K^{\pi }=4^{+}$ band based at 1646 keV; and $8^{-}$ and $9^{-}$ members of a $K=7\mathrm{}$ band based on the $7^{-}$ state at 2138 keV. The results are compared with various theoretical models. $\gamma -\gamma$ directional correlation measurements were also performed on some cascades populated in the radioactive decay of the various isomers of ${}_{}{}^{154}{}_{}{}^{}\mathrm{Tb}$, and the results confirm the assignment of $7^{-}$ for the 2137.8 keV state and establish a spin value of 1 for the 2119.7 and 2187.2 keV states.

NUCLEAR REACTIONS ${}_{}{}^{152}{}_{}{}^{}\mathrm{Sm}(\alpha , 2n\gamma )$, $E=24\mathrm{}$ MeV, measured $E_{\gamma }$, $I_{\gamma }$, $\gamma \gamma$ (delay), $\gamma \gamma$ coin, $\gamma \left(\theta \right)$ ${}_{}{}^{154}{}_{}{}^{}\mathrm{Gd}$ deduced levels, $K$, $J$, $\pi$, $\delta$, $Q$. Enriched targets. Ge(Li) detectors. RADIOACTIVITY ${}_{}{}^{154}{}_{}{}^{}\mathrm{Tb}$(22.6, 9.0, and 21.4 h) from ${}_{}{}^{153}{}_{}{}^{}\mathrm{Eu}(\alpha , 3n)$ and ${}_{}{}^{155}{}_{}{}^{}\mathrm{Gd}(p, 2n)$. Measured $\gamma \gamma \left(\theta \right)$ ${}_{}{}^{154}{}_{}{}^{}\mathrm{Gd}$ deduced $J$, $\pi$, $\delta$. Enriched targets. Ge(Li) detectors.

The ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}(\overrightarrow{t}, \alpha )$ ${}_{}{}^{153}{}_{}{}^{}\mathrm{Pm}$ reaction has been studied using a 17 MeV beam of polarized tritons from the tandem Van de Graaff accelerator at the Los Alamos Scientific Laboratory. The $\alpha$ spectra were recorded using a quadrupole-dipole-dipole-dipole magnetic spectrometer with a position-sensitive helical-cathode detector on the focal plane. Spectra were obtained to excitation energies > 2 MeV with a resolution of ∼ 17 keV. It was possible to assign spins and parities to many of the levels by comparing the measured angular distributions of cross sections and analyzing powers with distorted-wave Born-approximation predictions. The results are interpreted in terms of the Nilsson model with pairing and Coriolis mixing effects included. The $\frac{5}{2^{-}}\mathrm{}\left[532\right]\mathrm{}$, $\frac{5}{2^{+}}\mathrm{}\left[413\right]\mathrm{}$, $\frac{3}{2^{+}}\mathrm{}\left[411\right]\mathrm{}$, and $\frac{1}{2^{+}}\mathrm{}\left[420\right]\mathrm{}$ bands have been observed, as well as the $\frac{3}{2^{-}}\mathrm{}\left[541\right]\mathrm{}$ and $\frac{3}{2^{+}}\mathrm{}\left[422\right]\mathrm{}$ orbitals, which appear to be strongly Coriolis mixed with the $\frac{1}{2^{-}}\mathrm{}\left[550\right]\mathrm{}$ and $\frac{1}{2^{+}}\mathrm{}\left[431\right]\mathrm{}$ states, respectively. The results of these experiments confirm some of the assignments from a recent ($d$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$) study and show that others were incorrect. Spectroscopic factors for the strongest transitions are in good agreement with expectations based on the model. The ground state $Q$ value for the ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}(t, \alpha ){}_{}{}^{153}{}_{}{}^{}\mathrm{Pm}$ reaction was measured to be 10.748±0.020 MeV.

NUCLEAR REACTIONS ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}(\overrightarrow{t}, \alpha ){}_{}{}^{153}{}_{}{}^{}\mathrm{Pm}$, $E=17\mathrm{}$ MeV, measured $\sigma (E_{\alpha }, \theta )$, $A_y(E_{\alpha }, \theta )$, $Q$ value. ${}_{}{}^{153}{}_{}{}^{}\mathrm{Pm}$ deduced levels, $I$, $\pi$, Nilsson assignments, enriched target.

Neutron capture $\gamma$-ray measurements following resonance capture have been performed upon enriched samples of ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}$ and ${}_{}{}^{58}{}_{}{}^{}\mathrm{Fe}$, and upon a natural Fe (91.7% ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$) sample. Twenty-eight $\gamma$ rays were observed from two resonances of the ${}_{}{}^{58}{}_{}{}^{}\mathrm{Fe}(n, \gamma )$ reaction, and nineteen were incorporated into a level scheme for ${}_{}{}^{59}{}_{}{}^{}\mathrm{Fe}$. Thirty-seven $\gamma$ rays were observed from the 1.167-keV resonance of the ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}(n, \gamma )$ reaction, and twenty-eight were incorporated into a level scheme for ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$. Two $\gamma$ rays were observed from four resonances of the ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}(n, \gamma )$ reaction. The neutron separation energy for ${}_{}{}^{59}{}_{}{}^{}\mathrm{Fe}$ was determined to be 6580.8 ± 1.0 keV.

NUCLEAR REACTIONS ${}_{}{}^{54,56}{}_{}{}^{}\mathrm{Fe}(n, \gamma )$, $E=1-50\mathrm{}$ keV, ${}_{}{}^{58}{}_{}{}^{}\mathrm{Fe}$ ($n, \gamma$), $E=0.1-11\mathrm{}$ keV; measured $E_{\gamma }$, $I_{\gamma }$. ${}_{}{}^{55}{}_{}{}^{}\mathrm{Fe}$ deduced resonances. ${}_{}{}^{57,59}{}_{}{}^{}\mathrm{Fe}$ deduced resonances, levels. ${}_{}{}^{59}{}_{}{}^{}\mathrm{Fe}$ deduced neutron separation energy. Enriched targets.

Angular distributions have been measured for transitions populating residual states in ${}_{}{}^{167}{}_{}{}^{}\mathrm{Er}$ through the ${}_{}{}^{168}{}_{}{}^{}\mathrm{Er}(d, t)$ reaction at $E_d=15, 13, 11, \mathrm{and} 9$ MeV. Many of these transitions were previously seen to have angular distribution shapes which agreed with distorted-wave Born-approximation predictions at 17 MeV and these transitions also agree well with distorted-wave Born-approximation predictions at the lower bombarding energies. A small but significant number of transitions exhibited anomalously shaped angular distributions at 17 MeV and these continue to have anomalous angular distributions at the lower bombarding energies. Spectroscopic factors do not vary significantly over the bombarding energy range $9\le E_d\le 17$ MeV. Spectroscopic factor disagreements between recent analyses of 17 MeV angular distributions and previously reported analyses of individual spectra at 12 MeV presumably do not result from a bombarding energy dependence but rather from the large uncertainties inherent in applying the distorted-wave Born-approximation analysis without having complete angular distributions.

NUCLEAR REACTIONS ${}_{}{}^{168}{}_{}{}^{}\mathrm{Er}(d, t)$, $E_d=15, 13, 11, \mathrm{and} 9$ MeV measured $\sigma \left(\theta \right)$; DWBA analysis, deduced levels, $l$ values, spectroscopic factors. Enriched targets.

The ${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$+$n$ reaction has been studied by means of high resolution neutron transmission and differential elastic scattering measurement. Information pertaining to resonance parameters ($E_n$, $l$, $J$, and ${\Gamma }_n$) for some 118 resonances in the energy interval from 3 to 485 keV has been obtained. Distributions of neutron strengths have been determined for each value of $J$ that can be formed by $s$-, $p$-, and $d$-wave neutrons interacting with the ${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$ ground state ($J^{\pi }=\frac{1}{2^{-}}$). The existence of a doorway state in the $J^{\pi }=1^{-}$, $s$-wave channel at ∼500 keV is confirmed. Evidence is also found for the presence of doorway states in the $p$-wave ($J^{\pi }=1^{+}$) and $d$-wave ($J^{\pi }=1^{-}$) channels. The doorway state in the $p$-wave channel is shown to be correlated with $M1\mathrm{}$ ground-state radiative strength in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$. In the energy region above the doorway state, the "average" $p$-wave strength function for forming $1^{+}$ resonances [$S^1\left(1^{+}\right)=(6.8\mathrm{}\pm 0.6)\times {10}^{-5\mathrm{}}$] is found to be equal to the sum of those for forming $0^{+}$ [$S^1\left(0^{+}\right)=(4.2\mathrm{}\pm 1.0)\times {10}^{-5\mathrm{}}$] and $2^{+}$ [$S^1\left(2^{+}\right)=(2.8\mathrm{}\pm 0.4)\times {10}^{-5\mathrm{}}$] resonances in agreement with predictions of the random phase assumption.

NUCLEAR REACTIONS ${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$ ($n$), ($n, n$), $E=3-485\mathrm{}$ keV; measured ${\sigma }_T\mathrm{}\left(E\right)\mathrm{}$, $\sigma (E, \theta )$. ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ deduced doorway states, resonance parameters, $J^{\pi }$, ${\Gamma }_n$, neutron strength functions.

$\alpha$ particles from the electrodisintegration of seven nuclei with $Z$ between 29 and 79 have been observed. Energy spectra at 50° in the laboratory for six nuclei and angular distribtions for five nuclei are reported. The cross sections exhibit a broad peak whose magnitude decreases with increasing $Z$; the energy of the peak increases as $Z$ increases. Angular distributions at the highest energies measured become increasingly forward peaked suggesting a direct-reaction process.

NUCLEAR REACTION ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}(e, \alpha )$, ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}(e, \alpha )$, ${}_{}{}^{159}{}_{}{}^{}\mathrm{Tb}(e, \alpha )$, ${}_{}{}^{166}{}_{}{}^{}\mathrm{Er}(e, \alpha )$, ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}(e, \alpha )$, $E=100\mathrm{}$ MeV; measured $\sigma (E_{\alpha }, \theta )$. ${}_{}{}^{162}{}_{}{}^{}\mathrm{Dy}(e, \alpha )$, ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}(e, \alpha )$, $E=100\mathrm{}$ MeV; measured $\sigma \left(E_{\alpha }\right)$. Natural and enriched targets.

Beams of 96 and 115 MeV $\alpha$ particles have been used to study the distribution of isoscalar octupole strength in 18 nuclei from ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ to ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$. A prominent broad peak ($\Gamma \sim 2.5$ MeV) is observed at $E_x\sim \frac{30}{A^{\frac{1}{3}}}$ MeV in nuclei from ${}_{}{}^{66}{}_{}{}^{}\mathrm{Zn}$ to ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$. No broad peak is observed in this excitation energy range in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ or ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ and lighter nuclei. The oscillatory angular distributions of the ($\alpha , {\alpha }^{\prime }$) reaction exciting this peak are in excellent agreement with $l=3\mathrm{}$ distorted-wave Born approximation calculations. Studies of the angular range from ${\sigma }_{\mathrm{lab}}=3.5\mathrm{}° \mathrm{to} 6°$ in ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$ indicate very little contribution from $l=1\mathrm{}$ strength. Energy- weighted sum rule fractions for this low-energy octupole resonance are generally in the range from 15% to 20%; this corresponds to ½ to $\frac{2}{3}$ of the expected $1\hslash \omega$ octupole strength. The overall distribution of octupole strength in spherical nuclei, including the absence of the low-energy octupole resonance in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$, is in very good agreement with random-phase approximation calculations. The low-energy octupole resonance undergoes a pronounced change in structure in soft-vibrational and deformed nuclei. Theoretical calculations for the low-energy octupole resonance in ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}$ account qualitatively for the data.

NUCLEAR REACTIONS ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, ${}_{}{}^{66}{}_{}{}^{}\mathrm{Zn}$, ${}_{}{}^{75}{}_{}{}^{}\mathrm{As}$, ${}_{}{}^{89}{}_{}{}^{}\mathrm{Y}$, ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$, ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$, ${}_{}{}^{100}{}_{}{}^{}\mathrm{Mo}$, Ag (nat), ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$, ${}_{}{}^{118}{}_{}{}^{}\mathrm{Sn}$, ${}_{}{}^{124}{}_{}{}^{}\mathrm{Sn}$, ${}_{}{}^{142}{}_{}{}^{}\mathrm{Nd}$, ${}_{}{}^{144}{}_{}{}^{}\mathrm{Sm}$, ${}_{}{}^{148}{}_{}{}^{}\mathrm{Sm}$, ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}$, ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$, ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}(\alpha , {\alpha }^{\prime })$, $E_{\alpha }=96, 115$ MeV measured $E_x$, $\sigma \left(\theta \right)$ giant resonances, deduced $l$, $\beta$.

Cross section and vector analyzing power for the elastic and inelastic scattering of 16 MeV deuterons on ${}_{}{}^{70,72,74}{}_{}{}^{}\mathrm{Ge}$ have been measured over the angular range 30° to 145°. In addition to the strongly excited $2_1^{+}$ and $3^{-}$ states, data have been obtained for the $0_2^{+}$, $2_2^{+}$, and $4_1^{+}$ levels, as well as for several more highly excited levels in each isotope. The results have been compared with both distorted-wave Born-approximation and coupled-channels calculations, the latter employing both vibrational and rotational models. Although the coupled-channels analysis does not permit an unambiguous distinction between these two models on the basis of the data for the $0_1^{+}$, $2_1^{+}$, and $4_1^{+}$ levels, the results are not inconsistent with a transition from oblate to prolate deformation between ${}_{}{}^{72}{}_{}{}^{}\mathrm{Ge}$ and ${}_{}{}^{74}{}_{}{}^{}\mathrm{Ge}$. Spin and parity assignments are given for some of the states above 2 MeV of excitation.

NUCLEAR REACTIONS ${}_{}{}^{70,72,74}{}_{}{}^{}\mathrm{Ge}$ ($\overrightarrow{d}, d^{\prime }$) $E=16.0\mathrm{}$ MeV; measured $i{T}_{11}$, $\sigma \left(\theta \right)$, deduced deformation parameters, ${\beta }_l$, $J$, $\pi$. Enriched targets.

Charge, energy, and angular distributions of products from reactions between ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ and Ni have been measured at 164 MeV. The total reaction cross section inferred from the quarter-point of the elastic scattering data is 2010 mb. Products with $6\le Z\le 20$ account for 30% of the total reaction cross section. The evaporation residue cross section was also measured and found to be 1236 mb, or 61% of the total cross section. Products with atomic number near that of the projectile have angular distributions which increase in the forward direction and have energy spectra characteristic of both quasielastic and deeply inelastic events. Products with atomic numbers greater than 14 show an angular distribution $\frac{d\sigma }{d\Omega }\propto \frac{1}{{sin\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}}$ and have kinetic energies that are characteristic of Coulomb repulsion following binary fission, indicating that complete damping has occurred. However, the yield near $Z=19\mathrm{}$ is low, and thus symmetric fission, if present at all, accounts for a rather small fraction of the total reaction cross section.

NUCLEAR REACTIONS ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ + Ni; $E=164\mathrm{}$ MeV; strongly damped; $10°<~{\psi }_{\mathrm{lab}}<~70°$; quasielastic; product energies, charge distributions, cross sections $\frac{d\sigma }{d{\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}}$; evaporation residue cross section ${\sigma }_{\mathrm{ER}}$; reaction cross section; gas ionization detector $\Delta E$; surface barrier detector $E$.