Cross sections for ($\alpha ,\alpha n$) reactions on ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$, ${}_{}{}^{65}{}_{}{}^{}\mathrm{Cu}$, and ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$ at 900 MeV have been determined relative to the ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}(\alpha ,\alpha 2pn){}_{}{}^{24}{}_{}{}^{}\mathrm{Na}$ monitor reaction. They are 49.3 ± 3.5, 64.6 ± 2.8, and 95.8 ± 1.4 mb, respectively. The cross section used for the monitor reaction at this energy was 22.0 mb; this was determined through a comparison of the ${}_{}{}^{24}{}_{}{}^{}\mathrm{Na}$ and ${}_{}{}^{18}{}_{}{}^{}\mathrm{F}$ activities produced in A1 foil by 920-MeV helium ions. The general trends observed in ($\alpha ,\alpha n$) cross sections as a function of target composition are discussed. The direct population of the (12-) to (2-) states of ${}_{}{}^{196}{}_{}{}^{}\mathrm{Au}$ is 0.07 and this suggests a mechanism of direct emission of the neutron from the target surface. The observed trend of $\sigma (\alpha ,\alpha n)$ with the neutron skin thickness of the target also supports this mechanism. These reactions are compared with the high-energy ($p,pn$) reactions of the same targets.

Lifetimes of low-lying excited states in the nuclei ${}_{}{}^{35}{}_{}{}^{}\mathrm{Cl}$ and ${}_{}{}^{37}{}_{}{}^{}\mathrm{Cl}$ have been measured by the Doppler-shift attenuation method. Energies (in keV) and lifetimes (in psec) were determined as follows: ${}_{}{}^{35}{}_{}{}^{}\mathrm{Cl}$: 1219.4±0.1 (${0.21}_{-0.04\mathrm{}}^{+0.06\mathrm{}}$), 1763.2 ± 0.1 (${0.49}_{-0.06\mathrm{}}^{+0.09\mathrm{}}$), 2645.7±0.2 (0.26 ± 0.06), 2693.5 ± 0.1 (<0.12), 3002.5 ± 0.5 (<0.08), 3162.60 ± 0.10 (>10); ${}_{}{}^{37}{}_{}{}^{}\mathrm{Cl}$: 1726.6 ± 0.1 (${0.17}_{-0.04\mathrm{}}^{+0.05\mathrm{}}$), 3087.0 ± 1.0 (<0.09), 3103.0 ± 0.2 (>10).

The states of ${}_{}{}^{86}{}_{}{}^{}\mathrm{Rb}$ were studied using the ${}_{}{}^{87}{}_{}{}^{}\mathrm{Rb}\mathrm{}(d,t)\mathrm{}{}_{}{}^{86}{}_{}{}^{}\mathrm{Rb}$ reaction at 17.5-MeV incident energy. Spectra were obtained using an Enge split-pole magnetic spectrograph; over-all energy resolution was 9 keV. Angular distributions were obtained from 9 to 60° laboratory angle for 25 levels up to 2 MeV excitation. Comparison with distorted-wave Born-approximation calculations yielded unique $l$-value assignments for 18 transitions; absolute spectroscopic factors were also extracted. Implications about the structure of the low-lying states are pointed out. The significant excitation of the $J^{\pi }=2^{-}$ ground state of ${}_{}{}^{86}{}_{}{}^{}\mathrm{Rb}$ indicates weak $3s_{\frac{1}{2}}$ and $2d_{\frac{5}{2}}$ admixtures in the ${}_{}{}^{87}{}_{}{}^{}\mathrm{Rb}$ ground state.

The ${}_{}{}^{88}{}_{}{}^{}\mathrm{Sr}(d,\alpha ){}_{}{}^{86}{}_{}{}^{}\mathrm{Rb}$ reaction has been studied with 17.00-MeV deuterons. Energy resolution of 11 keV was obtained using an Enge split-pole spectrograph. Accurate excitation energies (±0.15%) were measured for more than 35 states up to an excitation energy of 3.3 MeV in the residual nucleus. Differential cross sections were obtained for most of the ${}_{}{}^{86}{}_{}{}^{}\mathrm{Rb}$ states for $12.5°\le \theta \le 65°$, and compared with distorted-wave calculations. The deduced $L$-transfer values allowed the assignment of a narrow range of $J^{\pi }$ values to 25 of these states. Several unique spin assignments were possible. Microscopic-model calculations were performed for several of the low-lying negative parity states in ${}_{}{}^{86}{}_{}{}^{}\mathrm{Rb}$, using simple two-component wave functions empirically derived from ${}_{}{}^{87}{}_{}{}^{}\mathrm{Rb}\mathrm{}(d,t)\mathrm{}$ spectroscopic factors. The predictions agreed reasonably well with the experimental ($d,\alpha$) data for both the relative magnitudes and the shapes of the angular distributions, except for the $J^{\pi }=2^{-}$ ground state.

The high-energy regions of the $\gamma$-ray spectra formed by thermal-neutron capture and by average resonance capture were measured with an annihilation-pair Ge(Li) spectrometer. The observed $\gamma$-ray lines reveal the presence of many new states in ${}_{}{}^{239}{}_{}{}^{}\mathrm{U}$, and the intensities of lines in the average resonance-capture spectra establish the parties and limit the spins of the states. The data are entirely consistent with what is expected from the set of single-particle configurations used by Braid et al. to interpret the states of four odd-$A$ curium isotopes - i.e., all states with excitation energies less than 890 keV are interpretable in terms of these configurations, and no unobserved states are predicted. The average widths of $E1\mathrm{}$, $M1\mathrm{}$, and $E2\mathrm{}$ transitions are compared with the results of other experiments and with theory. The average $E1\mathrm{}$ and $M1\mathrm{}$ widths are consistent with what is expected, but the average $E2\mathrm{}$ width is unusually large. The unusual strength of one $E1\mathrm{}$ transition is discussed. The relationship between the branching ratios for thermal-neutron capture and for resonance capture is discussed in an appendix.

The low-lying states of ${}_{}{}^{94,98,100}{}_{}{}^{}\mathrm{Mo}$ have been investigated via multiple Coulomb excitation effected with 7.2-MeV $\alpha$ particles and 35- to 44.8-MeV oxygen projectiles. In the three isotopes studied $2^{+}$ and $4^{+}$ levels were excited up to 2.1 MeV. The double $E2\mathrm{}$ excitation of a $0^{+}$ level at 694.4 keV in ${}_{}{}^{100}{}_{}{}^{}\mathrm{Mo}$, very close in energy to the first $2^{+}$ excited state, was observed. The $E2\mathrm{}$ transition between the $0^{+\prime }$ level and the first $2^{+}$ state is strongly enhanced, i.e., $\frac{B(E2;0^{+\prime }\to 2^{+})}{B(E2;2^{+}\to 0^{+})}=1.8\mathrm{}\pm 0.3$. The values obtained for the ratio $\frac{B(E2;2^{+\prime }\to 2^{+})}{B(E2;2^{+}\to 0^{+})}$ and the ratio $\frac{B(E2;4^{+}\to 2^{+})}{B(E2;2^{+}\to 0^{+})}$ are 2.6 ± 0.6, 2.5 ± 0.4, 1.69 ± 0.22 and 1.53 ± 0.24, 2.3 ± 0.3, 1.85 ± 0.19, respectively, for ${}_{}{}^{94}{}_{}{}^{}\mathrm{Mo}$, ${}_{}{}^{98}{}_{}{}^{}\mathrm{Mo}$, and ${}_{}{}^{100}{}_{}{}^{}\mathrm{Mo}$. States at 2533.7, 2017.6, and 1908.1 keV have been excited in ${}_{}{}^{94}{}_{}{}^{}\mathrm{Mo}$, ${}_{}{}^{98}{}_{}{}^{}\mathrm{Mo}$, and ${}_{}{}^{100}{}_{}{}^{}\mathrm{Mo}$, respectively. These states are interpreted to be the result of direct $E3\mathrm{}$ Coulomb excitation. Their $B(E3,0^{+}\to 3^{-})$ values are 6.2 ± 1.2 (${}_{}{}^{94}{}_{}{}^{}\mathrm{Mo}$), 13.3 ± 1.3 (${}_{}{}^{98}{}_{}{}^{}\mathrm{Mo}$), and 13.2 ± 1.7 (${}_{}{}^{100}{}_{}{}^{}\mathrm{Mo}$) × ${10}^{-2\mathrm{}}$ ${\mathit{e}}^2$${\mathrm{b}}^3$ which represent enhancements of 17, 33, and 32, respectively.

The results of a search for elements in the region of atomic number 114 are reported. More than 40 large samples of ores, naturals minerals, and other possible sources have been investigated. The method of detection made use of a large liquid scintillator to detect spontaneous fission events in which unusually large numbers of neutrons are emitted. The apparatus was located in a tunnel under about 250 m of earth shielding in order to reduce the interfering effects of cosmic rays. The limit set for the ratio of half-life/concentration for all the materials tested was greater than ${10}^{23}$ yr/concentration. If the half-life were ${10}^9$ yr this limit would correspond to a concentration of less than ${10}^{-14\mathrm{}}$ moles of superheavy elements per mole of sample.

The thick-target-thick-catcher technique was used to determine the recoil properties of some rare-earth nuclides produced by the interaction of 28-GeV protons with uranium and gold. Mean momenta derived from this and other experiments are discussed in terms of fission and spallationlike processes. It is concluded that, while fission can account for neutron-rich products from uranium, the momenta of neutron-deficient rare-earth nuclides from both uranium and gold are too low to arise from any conventional fission process. In the mass region below the rare earths, many neutron-deficient isotopes appear to be formed by mixed mechanisms. Only the most neutron-deficient products have momenta as low as those predicted for a spallationlike process. Mean cascade deposition energies, $E^{*}$, derived from the forward to backward ratios average 145 MeV for the neutron-deficient rare earths from uranium and 199 MeV for these products from gold. Such low values for gold and the even lower values for uranium cannot be understood in terms of a model for the spallationlike process involving a nucleonic cascade followed by conventional evaporation. Either there is a break-down of the two-step model, e.g. as might be expected if fragment emission is involved, or it is not valid to extrapolate to 28 GeV the momentum-transfer excitation-energy relationship inferred from Monte Carlo calculations at much lower energies.

The nuclides ${}_{}{}^{143}{}_{}{}^{}\mathrm{Sm}$, ${}_{}{}^{141}{}_{}{}^{}\mathrm{Nd}$, and ${}_{}{}^{140}{}_{}{}^{}\mathrm{Pr}$ were prepared by the ($n,2n$) reaction using energetic neutrons produced by deuteron bombardment of tritium and lithium targets. A comparison of $K$ x rays and annihilation radiation from each nuclide was made by means of a thin-window NaI detector. Using theoretical ratios of $K$ electron capture to total electron capture, percentages of positron emission for ${}_{}{}^{143}{}_{}{}^{}\mathrm{Sm}$, ${}_{}{}^{141}{}_{}{}^{}\mathrm{Nd}$, and ${}_{}{}^{140}{}_{}{}^{}\mathrm{Pr}$ were found to be 40.0 ± 2.0, 2.72 ± 0.20, and 48.7 ± 2.2, respectively.

Properties of levels in ${}_{}{}^{241}{}_{}{}^{}\mathrm{Pu}$ and ${}_{}{}^{243}{}_{}{}^{}\mathrm{Pu}$ were determined by ($d,p$) and ($d,t$) reactions on targets of ${}_{}{}^{240}{}_{}{}^{}\mathrm{Pu}$ and ${}_{}{}^{242}{}_{}{}^{}\mathrm{Pu}$. The reactions ${}_{}{}^{240}{}_{}{}^{}\mathrm{Pu}(n,\gamma ){}_{}{}^{241}{}_{}{}^{}\mathrm{Pu}$ and ${}_{}{}^{241}{}_{}{}^{}\mathrm{Pu}(d,d^{\prime }){}_{}{}^{241}{}_{}{}^{}\mathrm{Pu}$ were also studied. On the basis of these data, single-particle assignments are made for levels in ${}_{}{}^{241}{}_{}{}^{}\mathrm{Pu}$ and ${}_{}{}^{243}{}_{}{}^{}\mathrm{Pu}$. Single-particle spectra, extracted from the data by means of a pairing-force calculation, are compared both with those of the isotonic nuclides and with the single-particle spectra calculated from a deformed Woods-Saxon potential.

The quadrupole moment of the 0.434-MeV $2^{+}$ state in ${}_{}{}^{108}{}_{}{}^{}\mathrm{Pd}$ has been measured by detecting the deexcitation $\gamma$ ray following Coulomb excitation in coincidence with scattered ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$ ions. If excitation via the second $2^{+}$ state interferes constructively with the direct excitation of the first $2^{+}$ state, i.e., increasing the excitation probability of the first $2^{+}$ state, $Q_{2^{+}}=-0.51\mathrm{}\pm 0.06$ b. If the interference is destructive, $Q_{2^{+}}=-0.30\mathrm{}\pm 0.06$ b. An attempt to determine the sign of the interference by measuring the energy dependence of the reorientation effect is also discussed.

An in-beam electron spectrometer was used to identify internal-conversion transitions resulting from proton bombardment of ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$ at 8.0 and 11.0 MeV.

The $K$- and $L$-subshell internal-conversion coefficients of the anomalous 150.4-keV transition in ${}_{}{}^{177}{}_{}{}^{}\mathrm{Lu}$ have been measured with a double-focusing electron spectrometer and a Ge(Li) $\gamma$-ray spectrometer. The analysis of the results gave the $M2\mathrm{}$ content, $Q=(0.92\mathrm{}\pm 0.88)\%$, and the penetration parameters, ${\lambda }_1=-21.4\mathrm{}\pm 2.3$, and ${\lambda }_2=-660\mathrm{}\pm 900$. Using these results along with the known lifetime of the 150.4-keV level, the $E1\mathrm{}$ and $M2\mathrm{}$ $\gamma$-ray matrix elements and the $\int {\overrightarrow{\mathrm{J}}}_n·\overrightarrow{\mathrm{r}}$ and the $\int {\overrightarrow{\mathrm{J}}}_n·\overrightarrow{\nabla }$ type penetration matrix elements were evaluated and compared with those of similar transitions in ${}_{}{}^{175}{}_{}{}^{}\mathrm{Lu}$ and ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$ and with the estimates of the Nilsson model.

The absolute value of ($n,p$) reaction cross sections, as given by the pre-equilibrium exciton model is estimated using Fermi gas approximation.

A general agreement with experimental data, particularly in the gross $A$ dependence is obtained. The energy range considered is 10-20 MeV, and the nuclei are those with $A>\mathrm{}100\mathrm{}$: In these ranges evaporation is negligible and the analysis is rather easy. The approximate life-time of one single-particle exciton in nuclear matter is also deduced.

In 18-MeV deuteron bombardments of enriched ${}_{}{}^{200}{}_{}{}^{}\mathrm{Hg}$, we have produced a new isomer 2.27 ± 0.05-day ${}_{}{}^{198m}{}_{}{}^{}\mathrm{Au}$, which is believed to be analogous to the $(h_{\frac{11}{2}}\pi ,i_{\frac{13}{2}}\nu ){12}^{-}$ isomer in ${}_{}{}^{196}{}_{}{}^{}\mathrm{Au}$. No ${\beta }^{-}$ branching is observed in the decay of ${}_{}{}^{198m}{}_{}{}^{}\mathrm{Au}$. The isomeric transition is followed by a cascade of 204.10- and 180.31-keV $\gamma$ rays to a 123-nsec level at 312.10 keV which deexcites to ground by a sequence of 97.21-keV ($E1\mathrm{}$) and 214.89-keV ($E2\mathrm{}$) transitions. A revised interpretation of the results of earlier ($n,\gamma$) and ($d,p\gamma$) studies of the ${}_{}{}^{198}{}_{}{}^{}\mathrm{Au}$ level structure is presented and shell-model assignments for the levels populated in the isomeric decay are proposed. It is argued that the $E1\mathrm{}$ deexcitation of the 123-nsec isomer involves the $l$-forbidden single-particle transition $(d_{\frac{3}{2}}\pi ,i_{\frac{13}{2}}\nu )5^{+}\to (d_{\frac{3}{2}}\pi ,f_{\frac{5}{2}}\nu )4^{-}$.

Energy levels of ${}_{}{}^{155,157,159,161}{}_{}{}^{}\mathrm{Tb}$ have been studied through the (${}_{}{}^3{}_{}{}^{}\mathrm{He},d$) and ($\alpha ,t$) reactions on ${}_{}{}^{154,156,158,160}{}_{}{}^{}\mathrm{Gd}$, run with 25.5-MeV ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ and 27.0-MeV $\alpha$ particles, respectively. Distortedwave Born-approximation analysis was used to interpret the reaction results, with transferred $l$ values obtained from the comparison of the experimental and theoretical values of the cross-section ratio, $R=\frac{d\sigma ({}_{}{}^3{}_{}{}^{}\mathrm{He},d)}{d\sigma (\alpha ,t)}$. The spectroscopic information obtained was compared to the theoretical predictions of the Nilsson model. Corrective terms added included the Coriolis and pairing interactions. Many of the levels excited were identified as members of rotational bands built on Nilsson single-particle configurations. Identified in all four nuclei are the [411↑], [413↓], [532↑], [404↓], [402↑], and [411↓] Nilsson configurations. Other bands identified are the [541↓] in ${}_{}{}^{157,159,161}{}_{}{}^{}\mathrm{Tb}$, the [523↑] in ${}_{}{}^{159,161}{}_{}{}^{}\mathrm{Tb}$, the [411↑] $\gamma$ mixed configuration in ${}_{}{}^{155,157,159}{}_{}{}^{}\mathrm{Tb}$, and the [514↑] configuration in ${}_{}{}^{155}{}_{}{}^{}\mathrm{Tb}$.

The decay of ${}_{93}{}^{232}{}_{}{}^{}\mathrm{Np}$ has been studied by $\gamma$ spectroscopy with a Ge(Li) spectrometer. The energies and relative intensities of 24 $\gamma$ peaks have been determined. A decay scheme with two new energy levels at 1098.2 and 1146.3 keV is proposed. The level at 1193.9 keV has been confirmed. Electron-capture branching intensities are given.

A search has been made for a 2.37-MeV $\gamma$ ray using the ${}_{}{}^{94}{}_{}{}^{}\mathrm{Zr}(n,n^{\prime }\gamma )$ reaction at an incident neutron energy of 5 MeV in an attempt to observe the 2.37-MeV ($2^{+}$) level seen in ${}_{}{}^{92}{}_{}{}^{}\mathrm{Zr}\mathrm{}(t,p)\mathrm{}{}_{}{}^{94}{}_{}{}^{}\mathrm{Zr}$ and ${}_{}{}^{96}{}_{}{}^{}\mathrm{Zr}\mathrm{}(p,t)\mathrm{}{}_{}{}^{94}{}_{}{}^{}\mathrm{Zr}$ reaction studies and predicted in an earlier ${}_{}{}^{94}{}_{}{}^{}\mathrm{Zr}(n,n^{\prime }\gamma \gamma )$ experiment. This $\gamma$ ray has not been observed. Other possible decay modes of the 2.37-MeV ($2^{+}$) level have been looked for and ruled out except for the unlikely case of the level decaying to several levels in such a way that no one level receives an appreciable amount of the decay. As a result we are left with the puzzle that the ${}_{}{}^{94}{}_{}{}^{}\mathrm{Zr}(n,n^{\prime }\gamma ){}_{}{}^{94}{}_{}{}^{}\mathrm{Zr}$ reaction excites a $4^{+}$ level at 2.336 MeV not seen in the ${}_{}{}^{92}{}_{}{}^{}\mathrm{Zr}\mathrm{}(t,p)\mathrm{}{}_{}{}^{94}{}_{}{}^{}\mathrm{Zr}$ and ${}_{}{}^{96}{}_{}{}^{}\mathrm{Zr}\mathrm{}(p,t)\mathrm{}{}_{}{}^{94}{}_{}{}^{}\mathrm{Zr}$ reactions. The ($t,p$) and ($p,t$) reactions excite a $2^{+}$ level at 2.37 MeV not observed in the ($n,n^{\prime }\gamma$) reaction.

Positron emission in the second-forbidden nonunique transition from the ground state of ${}_{}{}^{207}{}_{}{}^{}\mathrm{Bi}$ to the first excited level of ${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$ was found to occur in (1.2 ± 0.2) × ${10}^{-4\mathrm{}}$ of all decays. Taking into account newly assigned relative intensities of the ${}_{}{}^{207}{}_{}{}^{}\mathrm{Bi}$ electron-capture decay branches, the $\frac{\mathrm{EC}}{{\beta }^{+}}$ ratio is found to be (6 ± 1) × ${10}^2$. From the ${\beta }^{+}$ intensity and the measured ${}_{}{}^{207}{}_{}{}^{}\mathrm{Bi}$ half-life of 38 ± 4 yr, it follows that $logft=12.6\mathrm{}\pm 0.1$ for this transition.

Transition rates and mean lifetimes for odd-parity levels of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$, and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ are obtained by using the wave functions of a renormalized random-phase approximation (RPA) treatment. For ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ the even-parity levels are also included.