The available experimental results on the equilibrium of the $\frac{N}{Z}$ degree of freedom are recalled. New available experimental results for very asymmetric systems are presented and compared to a simple classical model including the mass diffusion, the relaxation of the neutron excess degree of freedom, and the subsequent evaporation. The agreement between this classical calculation and the experiment is shown to be satisfactory.

NUCLEAR REACTIONS ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$+${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$, ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$+${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$+${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}$+${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}$, ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$+${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}$. Deeply inelastic reactions. Comparison of experimental distributions with a classical model.

In the time-dependent Hartree-Fock approximation, the fermions are assumed to interact only through the mean field and the collisions between particles are neglected. We formulate an extended time-dependent Hartree-Fock approximation which incorporates particle collisions due to the residual interaction, with the usual time-dependent Hartree-Fock approximation as the collisionless limit. It is obtained by a truncation of the Martin-Schwinger hierarchy at the second level and by using a simple representation of the one-body Green's function in terms of time-dependent occupation numbers. The final set of coupled equations consists of a modified time-dependent Hartree-Fock equation and a master equation for the occupation numbers. These results are physically transparent and describe properly the physics of the collision process. They may also be simple enough to be of practical use to study heavy-ion collisions or the dynamics of other fermion systems. Furthermore, as the configuration-space analog of the quantum Boltzmann equation, many important results concerning statistical dynamics are obtained. Concepts such as entropy, temperature, and local and thermal equilibrium can be quantitatively introduced. The well-known $H$ theorem that entropy never decreases can be readily recovered. With the collision term explicitly exhibited, the macroscopic equations (equations of continuity, momentum flux, and energy) and their associated conservation theorems can also be derived. Analytic solutions for the master equation for simple cases lead to new "level crossing" formulas having characteristics distinctly different from the Landau-Zener level-crossing formula and illuminate the salient features as to how a nonequilibrium fermion system approaches thermal equilibrium.

NUCLEAR REACTIONS Extension of time-dependent Hartree-Fock approximation. Collisions between particles. Master equation for occupation probabilities. Entropy, temperature, and thermal equilibrium. $H$ theorem. Analytic solution of the master equation. New types of level crossing formula.

Within an extended semiquantal theory we perform large-sized coupled-channel calculations involving 260 collective levels for Coulomb fission of ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$. Differential Coulomb fission cross sections are studied as a function of bombarding energy and impact parameter for several projectiles. In the Xe + U case, total cross sections are also given. We find a strong dependence on projectile charge number, $P^{\mathrm{CF}}\left(180\mathrm{}°\right)\sim {\left(Z_p\right)}^6$ in the region $50\le Z_p\le 92$ for a fixed ratio $\frac{E}{E_{\mathrm{Coul}}}$, which might be helpful to separate Coulomb fission experimentally from sequential fission following transfer reactions. Since the cross sections are sensitive to the moment of inertia $\ominus$ at the saddle point, Coulomb fission can serve as a tool to investigate the dependence of $\ominus$ on elongation. The fragment angular distribution exhibits deviations from $\frac{1}{{sin\theta }_f}$ which are pronounced at low incident energies. Our theory indicates that the recently measured Xe + U fission cross sections contain a major fraction of Coulomb-induced fission at $E\le 0.85E_{\mathrm{Coul}}$.

NUCLEAR REACTIONS, FISSION Calculated Coulomb fission cross sections $\sigma (E_p,{\theta }_p)$ for ${}_{54}{}^{}{}_{}{}^{}\mathrm{Xe}$, ${}_{67}{}^{}{}_{}{}^{}\mathrm{Ho}$, ${}_{82}{}^{}{}_{}{}^{}\mathrm{Pb}$, ${}_{92}{}^{}{}_{}{}^{}\mathrm{U}$→${}_{92}{}^{238}{}_{}{}^{}\mathrm{U}$, fragment angular distribution, fission energy spectrum, mean spin value $〈J_f〉$.

Cross sections and thick-target recoil properties of ${}_{}{}^{131}{}_{}{}^{}\mathrm{Ce}$, ${}_{}{}^{131}{}_{}{}^{}\mathrm{La}$, ${}_{}{}^{131}{}_{}{}^{}\mathrm{Ba}$, and several neighboring Ba nuclides formed in the interaction of ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ with 0.8-11.5 GeV protons have been determined. The results reveal a dichotomy between ${}_{}{}^{131}{}_{}{}^{}\mathrm{Ba}$ and the more neutron-rich products on the one hand, and the more neutron-deficient ones on the other. The latter have rising excitation functions, forward-to-backward ratios (F/B) that peak at 3 GeV, and ranges that decrease abruptly just below this energy. The former have decreasing excitation functions as well as F/B and ranges that decrease slowly and featurelessly with increasing proton energy. The energy dependence of F/B as well as the changes in the angular distributions of the very neutron deficient products observed between 3 and 11.5 GeV are explained in terms of a change in the nature of near-central proton-nucleus interactions. At the lower energies the interaction consists of a series of nucleon-nucleon collisions while at high energies the proton interacts collectively with all the nucleons lying in its path. The dropoff in the mean ranges of these same nuclides and the accompanying broadening of the spectra indicate a transition between fission and deep spallation. The possible connection between these two effects is discussed. Several experiments to test the proposed model are suggested.

NUCLEAR REACTIONS Measured $\sigma$, range, and F/B of ${}_{}{}^{131}{}_{}{}^{}\mathrm{Ce}$, ${}_{}{}^{131}{}_{}{}^{}\mathrm{La}$, ${}_{}{}^{131}{}_{}{}^{}\mathrm{Ba}$, ${}_{}{}^{128}{}_{}{}^{}\mathrm{Ba}$, ${}_{}{}^{133}{}_{}{}^{}\mathrm{Ba}_{}^m{}_{}{}^{}$, ${}_{}{}^{135}{}_{}{}^{}\mathrm{Ba}_{}^m{}_{}{}^{}$, and ${}_{}{}^{140}{}_{}{}^{}\mathrm{Ba}$ formed in interaction of ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ with 0.8-11.5 GeV protons. Proposed explanation for change in properties of very neutron deficient products.

The differential cross section for the $\mathrm{pd}\to d{\pi }^{+}n$ reaction at 800 MeV was measured in a kinematically complete experiment in regions of phase space where the neutron in the target deuteron recoils with near zero momentum. It was observed that the reaction basically proceeds through a quasifree process where the neutron is a spectator to the $\mathrm{pp}\to d\pi$ reaction. A calculation using the simple spectator model predicts the measured cross section when the neutron recoil momentum is near zero. At neutron recoil momenta of about 100 MeV/c, the cross section is approximately 35% lower than the data.

NUCLEAR REACTIONS ${}_{}{}^2{}_{}{}^{}\mathrm{H}(p,d{\pi }^{+})n$, $E=800\mathrm{}$ MeV; measured $\sigma (P_d, {\theta }_d, {\theta }_{\pi })$ model with spectator neutron. Deduced validity of spectator model.

Angular distributions for the elastic and inelastic scattering of 800 MeV protons from ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ are presented. Results of distorted-wave Born-approximation (DWBA) and coupled-channels (CC) analyses of the data for the $0_1^{+}$, $2_1^{+}$, $4_1^{+}$, and $6_1^{+}$ members of the ground state rotational band, the $2_2^{+}$, $3_2^{+}$, $4_2^{+}$, and $5_2^{+}$ members of the $\gamma$ band and the $0^{+}$ member of the $\beta$ band are discussed, and the effects of ground state deformation and multistep contributions are assessed. The DWBA calculations for the $4_1^{+}$ and $6_1^{+}$ angular distributions fail to even qualitatively reproduce the data, while a CC calculation, using a symmetric rotator model with quadrupole and hexadecapole ground state deformations, provides good fits for the $0_1^{+}$, $2_1^{+}$, and $4_1^{+}$ angular distributions. A CC calculation in which the ground band is coupled to the $\gamma$ band, with an assumed asymmetric vibrational amplitude, gives a fair fit to the data for the $2_2^{+}$ state, but fails to fit the $3_2^{+}$, $4_2^{+}$, and $5_2^{+}$ data. This failure in the calculation may be due to the lack of a direct step to the $4_2^{+}$ state, as well as neglect of the spin-flip process. The result of coupling the ground band with the 6.43 MeV $0_{\beta }^{+}$ state indicates that this axially symmetric deformed vibrational model may be essentially correct, but also seems to indicate that a direct $0_1^{+}-0_{\beta }^{+}$ step needs to be considered, based on the behavior of the forward angle $0_{\beta }^{+}$ data. Additional coupling of a $2_{\beta }^{+}$ state does not dramatically improve the fit to the $0_{\beta }^{+}$ data. The results obtained here from analyses of the 800 MeV data are compared with those obtained through analyses of lower energy data.

NUCLEAR REACTIONS ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$($p$,$p^{\prime }$) $E=0.8\mathrm{}$ GeV, measured $\sigma \left(\theta \right)$; enriched target; resolution ≥ 80 keV, ${\theta }_{\mathrm{cm}}=8\mathrm{}° \mathrm{to} 32°$, $\Delta \theta =0.1\mathrm{}°$. Optical model potential, DWBA analysis, coupled-channels analysis, symmetric and asymmetric rotator model, coupling parameters.

Cross sections for the formation of rubidium isotopes 83, 84, and 86 have been determined for targets from yttrium to uranium irradiated by protons of 0.6, 10.5, and 21 GeV. The recoil technique, using thick targets and thick collectors, combined with a mathematical formalism based on the two step model, permits the determination of some characteristics of the nuclear reactions, i.e., the range $R$, the mean momentum $〈P〉$ of the observed products, and the excitation energy $E^{*}$ of the residual nucleus after cascade. For the three Rb isotopes at 0.6 GeV, the mean momenta fall into three groups depending on the nature of the targets: (a) less than 30 ${\mathrm{}\left(\mathrm{MeV}\mathrm{u}\right)\mathrm{}}^{\mathrm{½}}$ for Y, Nb, and Ag but proportional to $\Delta A$, the difference between the target and product masses, (b) about 40 to 55 ${\mathrm{}\left(\mathrm{MeV}\mathrm{u}\right)\mathrm{}}^{\mathrm{½}}$ for the rare earths, and (c) from 55 to 120 ${\mathrm{}\left(\mathrm{MeV}\mathrm{u}\right)\mathrm{}}^{\mathrm{½}}$ for Ta to U. For 0.6, 10.5, and 21 GeV protons, the mean momenta are all practically the same as for the first two groups of targets. On the contrary, for ${}_{}{}^{83}{}_{}{}^{}\mathrm{Rb}$ and ${}_{}{}^{84}{}_{}{}^{}\mathrm{Rb}$ formed in targets Ta to U, the momenta decrease decidedly between 0.6 and 10.5 GeV. The mean momentum of ${}_{}{}^{86}{}_{}{}^{}\mathrm{Rb}$ formed in Th and U seems almost the same at 10.5 and 0.6 GeV. The excitation energies $E^{*}$ are very similar for 0.6, 10.5, and 21 GeV protons for all nuclear reactions where the mean momentum depends only slightly on $E_p$. However, the apparent value of $E^{*}$ diminishes for targets showing a decrease of mean momentum at 10.5 and 21 GeV. A semi-empirical test, based on the mean squared momentum $〈{m_i}^2{v_i}^2〉$ per evaporated nucleon, allows the production of Rb from Y, Nb, and Ag to be interpreted as spallation. Comparison of the experimental momenta or kinetic energies $〈T〉$ with values $\overline{E}$ calculated from the liquid drop model suggests binary fission at medium energies for the production of all three isotopes from targets of Ta to U with 0.6 GeV protons. The same conclusion is reached for the production of ${}_{}{}^{86}{}_{}{}^{}\mathrm{Rb}$ from Th and U for all incident energies employed. Reactions showing anomalous behavior of $E^{*}$ not explicable by the fission or simple spallation could result from a high energy mechanism.

NUCLEAR REACTIONS ${}_{}{}^{83}{}_{}{}^{}\mathrm{Rb}$, ${}_{}{}^{84}{}_{}{}^{}\mathrm{Rb}$, ${}_{}{}^{86}{}_{}{}^{}\mathrm{Rb}$ in 13 targets (Y to U), 0.6-10.5-21 GeV $E_p$. Measured cross sections $\sigma$ and thick target-thick collectors recoil properties. Derived deposition energy $E^{*}$, kinetic energy $T$ and momentum per emitted nucleon.

Spallation ratios and production cross sections of ${}_{}{}^{36,38,39,42}{}_{}{}^{}\mathrm{Ar}$ have been measured for the interaction of 0.080, 0.150, 0.600, 1.05, and 24 GeV protons with scandium, titanium, iron, cobalt, nickel, and copper. Argon is measured by means of a 60° 12 cm radius mass spectrometer, equipped with a gas extraction line and a calibration system. Precision is 1 to 5% for isotope ratios, and 10 to 20% for the cross sections. With regard to spallation reactions, some systematic effects are shown or confirmed. Excitation functions go through a maximum at high energy, then drop asymptotically to a constant value. The ratio of maximum to asymptote cross sections is about 1.6. The spallation ratios depend linearly on the ${\left(\frac{N}{Z}\right)}_T$ ratios of the target and there is probably a linear correlation between the position of the peak of the spallation distribution and the ${\left(\frac{N}{Z}\right)}_T$ ratio. Experimental values are compared with semiempirical fits and some astrophysical implications are discussed.

NUCLEAR REACTIONS Spallation; targets Sc, Ti, Fe, Co, Ni, Cu; protons 0.080, 0.150, 0.600, 1.05, 24 GeV; measured $\sigma$ for formation of ${}_{}{}^{36,38,39,42}{}_{}{}^{}\mathrm{Ar}$; mass spectrometry; $\sigma$ compared with semiempirical calculations; astrophysical implications.

A joint fit has been made to the binding energy data of the $A=3-4\mathrm{}$ hypernuclei (ground and excited states) together with the $\Lambda -p$ scattering data in order to deduce depth and range parameters of a phenomenological $\Lambda$-nucleon potential. Having determined the potential parameters we were able to infer the scattering lengths and effective ranges for the $\Lambda -p$ and $\Lambda -n$ systems.

NUCLEAR REACTIONS $\Lambda$-nucleon potential inferred from the data; effective range parameters calculated.

The half-life of ${}_{}{}^{232}{}_{}{}^{}\mathrm{U}$ was determined by two independent methods: a specific activity method and a relative activity method involving the half-life of ${}_{}{}^{233}{}_{}{}^{}\mathrm{U}$. In the specific activity method, the $\alpha$ disintegration rate of ${}_{}{}^{232}{}_{}{}^{}\mathrm{U}$ was determined by liquid scintillation counting as well as by $\alpha$ proportional counting, and the number of atoms of ${}_{}{}^{232}{}_{}{}^{}\mathrm{U}$ was determined by isotope dilution mass spectrometry. The radiochemical purity of the purified ${}_{}{}^{232}{}_{}{}^{}\mathrm{U}$ was confirmed by $\alpha$ spectrometry. A half-life value of 69.00±0.40 yr was obtained. In the relative activity method, synthetic mixtures were prepared using isotopes of ${}_{}{}^{232}{}_{}{}^{}\mathrm{U}$ and ${}_{}{}^{233}{}_{}{}^{}\mathrm{U}$. The $\alpha$ activity ratios in these mixtures were determined by $\alpha$ spectrometry and the atom ratios were obtained by mass spectrometry. The $\alpha$ activity ratios and the atom ratios were such that these could be measured with a high precision and accuracy. A half-life value of 68.81±0.38 yr was obtained using the half-life of ${}_{}{}^{233}{}_{}{}^{}\mathrm{U}$ as 1.592 × ${10}^5$ yr. The average of these two independent determinations leads to a value of 68.90±0.39 yr for the half-life of ${}_{}{}^{232}{}_{}{}^{}\mathrm{U}$. The uncertainty given on the values is a combination of the one standard deviation on the average value and the error evaluated from estimates on various error components. The values reported earlier are significantly higher as compared to the half-life value obtained in this work.

RADIOACTIVITY ${}_{}{}^{232}{}_{}{}^{}\mathrm{U}$ half-life, specific activity; measured: $\alpha$ activity by liquid scintillation counter and $\alpha$ proportional counter, uranium concentration by isotope dilution mass spectrometry; relative to the half-life of ${}_{}{}^{233}{}_{}{}^{}\mathrm{U}$; measured: ${}_{}{}^{232}{}_{}{}^{}\mathrm{U}$/${}_{}{}^{233}{}_{}{}^{}\mathrm{U}$ activity ratio by $\alpha$ spectrometry, ${}_{}{}^{232}{}_{}{}^{}\mathrm{U}$/${}_{}{}^{233}{}_{}{}^{}\mathrm{U}$ atom ratio by mass spectrometry.

Energy levels in ${}_{}{}^{68}{}_{}{}^{}\mathrm{Cu}$ are calculated using the core-coupling model. Levels in the odd nuclei ${}_{}{}^{65}{}_{}{}^{}\mathrm{Cu}$, ${}_{}{}^{67}{}_{}{}^{}\mathrm{Cu}$, and ${}_{}{}^{69}{}_{}{}^{}\mathrm{Zn}$ are first calculated to find the appropriate core-coupling parameters. These parameters are then used along with a zero-range proton-neutron interaction to calculate levels in ${}_{}{}^{68}{}_{}{}^{}\mathrm{Cu}$. In the model the second excited state is predicted to be a $3^{+}$ level rather than the ($3^{-}$) level currently assigned in the nuclear data sheets. The ordering of the quartet formed by coupling the $p_{\frac{3}{2}}$ proton to the $g_{\frac{9}{2}}$ neutron is predicted to be $6^{-}$, $3^{-}$, $4^{-}$, $5^{-}$.

NUCLEAR STRUCTURE Core-coupling model calculation of energy levels in ${}_{}{}^{68}{}_{}{}^{}\mathrm{Cu}$, ${}_{}{}^{65}{}_{}{}^{}\mathrm{Cu}$, ${}_{}{}^{67}{}_{}{}^{}\mathrm{Cu}$, ${}_{}{}^{69}{}_{}{}^{}\mathrm{Zn}$, ${}_{}{}^{67}{}_{}{}^{}\mathrm{Ni}$.

The collection path $\left|\phi \mathrm{}\right(q)\mathrm{}〉$ to be used in a microscopic description of large amplitude collective motion is determined by means of the generator coordinate method. By varying the total energy with respect to $\left|\phi \mathrm{}\right(q)\mathrm{}〉$ and performing an adiabatic expansion a hierarchy of equations is obtained which determines uniquely a hierarchy of collective paths with increasing complexity. To zeroth order the $\left|\phi \mathrm{}\right(q)\mathrm{}〉$ are Slater determinants, to first order they include 2p-2h correlations. In both cases simple noninterative prescriptions for an explicit construction of the path are derived. For a correlated path their solutions agree at the Hartree-Fock minimum with random phase approximation eigenmodes. The resulting equations for the path are compared with the outcome of related theories, particularly of semiclassical nature. It is remarkable that both sorts of approaches, on one hand the generator coordinate method with correlated states and on the other the quantized adiabatic time dependent Hartree-Fock theory, are virtually identical in the results, although they are of different conceptual origin and use different techniques. It is shown that the use of a correlated path does not cause numerical complications.

NUCLEAR STRUCTURE Collective path derived by GCM, inclusion of RPA correlations, relation to adiabatic TDHF.

A general method is presented for eliminating, in the theoretical values of the nuclear mass-tensor components, the unphysical effects due to the nuclear number fluctuation allowed by the usual BCS wave functions. General formulas for number-projected orthonormalized pairing wave functions and their energies are established in the quasiparticle representation. Analytical expressions are given for the pertinent pairing correlation matrix elements and overlap integrals, with strict nucleon number conservation. The importance and validity of the physical and mathematical approximations used are discussed. The tensor so obtained, without number dispersion spurious effects, is compared to the pure BCS tensor.

NUCLEAR STRUCTURE Inertial-mass tensor calculated in cranking model with number-projected BCS functions; SBCS theory; fission.

The repulsive hard core of a pair-wise interaction acting between fermions is simulated by a constraint to be included in the variational principle. The Euler-Lagrange equations are usual Hartree-Fock equations with a self-consistent one-body pseudopotential. It can be seen that the imposed constraint generates a correlation field in addition to the regular portion of the two-body interaction. The origin of density waves in coordinate space is discussed in terms of the hard-core correlations.

NUCLEAR STRUCTURE hard-core potentials, constrained Hartree-Fock, correlation field, pseudopotential; localized single-particle orbitals in nuclear matter.

The negative zero eigenvalues in the unitary pole expansion for hard core potentials are shown to contribute nothing to the exact $t$ matrix. We suggest that approximations involving these terms can account for the observed loss of convergence for the unitary pole expansion.

NUCLEAR STRUCTURE $t$ matrix, unitary pole expansion, hard core potentials.

The proton charge distribution, deduced from electron-proton scattering data, was used to calculate the Coulomb interaction between protons in nuclei in the $f-p-g$ shell. The Coulomb energies and shifts between members of the $A=42\mathrm{}$ isotopic spin triplet were calculated.

NUCLEAR STRUCTURE Derived the Coulomb potential between protons in $f-p-g$ shell. Calculated Coulomb energy in ${}_{}{}^{42}{}_{}{}^{}\mathrm{Ti}$ and shifts (${}_{}{}^{42}{}_{}{}^{}\mathrm{Ti}$-${}_{}{}^{42}{}_{}{}^{}\mathrm{Ca}$) and (${}_{}{}^{42}{}_{}{}^{}\mathrm{Sc}$-${}_{}{}^{42}{}_{}{}^{}\mathrm{Ca}$). Compared with experiment.

The $\gamma$-ray yield from 2.00 to 4.1 MeV proton bombardment of ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$ has been investigated. A single resonance is observed at $E_p=3.03\mathrm{}$ MeV in the yield of 0.43 MeV $\gamma$ rays.

NUCLEAR REACTIONS ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$($p$,$\alpha \gamma$)${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ and ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$($p$,$p^{\prime }\gamma$)${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$, $E=2.0-4.1\mathrm{}$ MeV; measured $E_{\gamma }$, $I_{\gamma }$. ${}_{}{}^{11}{}_{}{}^{}\mathrm{C}$ deduced levels. Enriched target.

Deuteron breakup cross sections induced by 28.6 MeV protons have been measured in collinear and noncollinear geometry and the results compared with an exact three-body calculation using the Doleschall code. This calculation includes two-body interactions in $S$ and $P$ waves and, in addition, a tensor force. The agreement with experiment in all cases is excellent. No evidence is seen for a collinearity enhancement.

NUCLEAR REACTIONS ${}_{}{}^2{}_{}{}^{}\mathrm{H}\mathrm{}(p,2p)n$, $E=28.6\mathrm{}$ MeV; measured cross section in collinear geometry; compared with exact three-body calculation.

Cross sections have been measured for the ($\alpha$,${\alpha }^{\prime }$) reaction leading to the first excited ($2^{+}$) state for targets of ${}_{}{}^{52}{}_{}{}^{}\mathrm{Cr}$, ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{58}{}_{}{}^{}\mathrm{Fe}$, and ${}_{}{}^{60}{}_{}{}^{}\mathrm{Ni}$. Data were obtained at several angles as a function of $E_{\alpha }$ in the region of 8 to 18 MeV. These energies cover the region of the isoscalar giant quadrupole resonance of the composite nuclei-${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$, ${}_{}{}^{60}{}_{}{}^{}\mathrm{Ni}$, and ${}_{}{}^{64}{}_{}{}^{}\mathrm{Zn}$. It has recently been reported that the giant quadrupole resonance of ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$, ${}_{}{}^{60}{}_{}{}^{}\mathrm{Ni}$, and ${}_{}{}^{62}{}_{}{}^{}\mathrm{Ni}$ decays primarily by $\alpha$ emission. Although the present data exhibit a giant resonancelike energy dependence, a coupled channels calculation indicates that several $J^{\pi }$ values can be expected to contribute to a resonancelike envelope in this reaction at the energies of the giant quadrupole resonance in these nuclei.

NUCLEAR REACTIONS ${}_{}{}^{52}{}_{}{}^{}\mathrm{Cr}$, ${}_{}{}^{54,58}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{60}{}_{}{}^{}\mathrm{Ni}$($\alpha$,${\alpha }_1$), $E_{\alpha }\cong 8 \mathrm{to} 14-19$ MeV; measured $\sigma (E_{\alpha };\theta )$. Targets ∼500 μg/${\mathrm{cm}}^2$ foils. Results examined for evidence of GQR and compared to coupled-channels calculation.

Inelastic scattering of 110 MeV ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ particles is used to probe the quadrupole strength in the even Mo isotopes. The peak position of the giant quadrupole resonance is found to decrease more rapidly than predicted by the $A^{-\frac{1}{3}}$ law, a behavior very similar to that exhibited by the photonuclear giant dipole resonance. The width and strength of the giant quadrupole resonance are practically constant in ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$ through ${}_{}{}^{100}{}_{}{}^{}\mathrm{Mo}$.

NUCLEAR REACTIONS ${}_{}{}^{100,98,96,94,92}{}_{}{}^{}\mathrm{Mo}$(${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$′), $E=110\mathrm{}$ MeV: Measured $\sigma (E,\theta )$. Position, width, and strength of the giant quadrupole resonance deduced.