Angular distributions from ∼12.5 to ∼45° were measured for ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}(d, p)$ and ${}_{}{}^{91}{}_{}{}^{}\mathrm{Zr}(d, p)$ at 33.3 MeV. The resolution was about 25 keV. A number of doublets were resolved, and levels were found that had not been reported in previous neutron-transfer studies. ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}(\alpha , {}_{}{}^3{}_{}{}^{}\mathrm{He})$ and ${}_{}{}^{91}{}_{}{}^{}\mathrm{Zr}(\alpha , {}_{}{}^3{}_{}{}^{}\mathrm{He})$ spectra with 55-keV resolution were obtained at 15 and 20° with 65.9-MeV $\alpha$ particles. The data are compared with distorted-wave predictions. The ($d, p$) spectroscopic factors agree with those from the ($\alpha$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$) reaction wherever comparisons are feasible. Sums of spectroscopic factors, centers of gravity, and second moments are presented for levels assigned to $d_{\frac{5}{2}}$, $s_{\frac{1}{2}}$, $d_{\frac{3}{2}}$, $g_{\frac{7}{2}}$, and $h_{\frac{11}{2}}$ configurations in each final nucleus. The sums are generally in agreement with the sum-rule predictions. The $h_{\frac{11}{2}}$ strength appears to be highly fragmented; in both nuclei, about 50% of the predicted strength was identified. The separations of the centers of gravity are similar for the two nuclei.

The study of nuclei which are one neutron removed from the $N=126\mathrm{}$ closed shell has shown that the odd-proton $N=127\mathrm{}$ isotones $\alpha$ decay from both the ground state and a metastable state whose excitation energy decreases between ${}_{}{}^{210}{}_{}{}^{}\mathrm{Bi}$ and ${}_{}{}^{216}{}_{}{}^{}\mathrm{Ac}$. The $\alpha$-decay daughters of these nuclei show some correspondence in their energy-level spacings which is due to the coupling of specific single-particle configurations near the $N=126\mathrm{}$ closed shell. New information has been obtained for the $\alpha$ decay of the 1 - isomer of ${}_{}{}^{214}{}_{}{}^{}\mathrm{Fr}$ to levels in ${}_{}{}^{210}{}_{}{}^{}\mathrm{At}$, and for the $\alpha$ decay of ${}_{}{}^{216}{}_{}{}^{}\mathrm{Ac}$ to levels in ${}_{}{}^{212}{}_{}{}^{}\mathrm{Fr}$. The decay scheme of ${}_{}{}^{216}{}_{}{}^{}\mathrm{Ac}$ is markedly different from that reported by others. An experimental and theoretical study of the $\alpha$ decay of ${}_{}{}^{215}{}_{}{}^{}\mathrm{Ra}$ has also been made.

Photoneutron cross sections, including $\sigma \left[\right(\gamma , n)+(\gamma , pn\left)\right]$, $\sigma (\gamma , 2n)$, and $\sigma (\gamma , 3n)$ for ${\mathrm{Ba}}^{138}$ and $\sigma \left[\right(\gamma , n)+(\gamma , pn\left)\right]$ for ${\mathrm{N}}^{14}$, were measured with monoenergetic photons from threshold to 29 MeV. The partial cross sections were determined by neutron multiplicity counting, and the average neutron energies for both single- and double-photoneutron events were determined simultaneously with the cross-section data by the ring-ratio technique. The ${\mathrm{N}}^{14}$ data, when combined with data from other laboratories, appears to show that the ($\gamma , \mathrm{pn}$) process dominates the decay of the giant resonance in this nucleus. The giant-resonance parameters for ${\mathrm{Ba}}^{138}$ are nearly the same as those for ${\mathrm{Pr}}^{141}$, which has the same (magic) neutron number.

The levels in ${}_{}{}^{140}{}_{}{}^{}\mathrm{La}$ have been studied following thermal-neutron capture in ${}_{}{}^{139}{}_{}{}^{}\mathrm{La}$ using Ge(Li), Si(Li), curved-crystal, and coincidence spectrometers. The neutron binding energy of ${}_{}{}^{140}{}_{}{}^{}\mathrm{La}$ was determined as 5161.1±1.0 keV. The data, when combined with the previous ${}_{}{}^{139}{}_{}{}^{}\mathrm{La}(d, p){}_{}{}^{140}{}_{}{}^{}\mathrm{La}$ study, allow the assignment of the first 14 states up to 581.060 keV to the mixed configurations $\pi g_{\frac{7}{2}}\nu f_{\frac{7}{2}}$ and $\pi d_{\frac{5}{2}}\nu f_{\frac{7}{2}}$. The energies of states in keV (spin parity) are: 0 ($3^{-}$), 29.965 ($2^{-}$), 34.656 ($5^{-}$), 43.811 ($1^{-}$), 48.865 ($6^{-}$), 63.171 ($4^{-}$), 103.803 ($6^{-}$), 162.656 ($2^{-}$), 272.311 ($4^{-}$), 284.634 ($7^{-}$), 318.214 ($3^{-}$), 322.003 ($5^{-}$), 467.505 ($1^{-}$), 581.060 ($0^{-}$). Comparisons of $\gamma$-ray branching ratios and ($d, p$) cross sections with the predictions of a quasiparticle model for odd-odd nuclei allow a relatively uncompromised solution for the state vectors for the first 14 states. The success of this model implies that there is little phonon or four-quasiparticle admixture through the level at 581.060 keV. A detailed experimental study of additional levels up to 1055 keV has been performed.

The angular distributions measured for 12 $\gamma$ rays in ${}_{}{}^{192}{}_{}{}^{}\mathrm{Os}$ and ${}_{}{}^{192}{}_{}{}^{}\mathrm{Pt}$ resulting from the decay of cryogenically oriented ${}_{}{}^{192}{}_{}{}^{}\mathrm{Ir}$ have been used to determine the following $\frac{E2\mathrm{}}{M1\mathrm{}}$ mixing ratios: 201 keV, ${\delta }^2>3.7\mathrm{}$; 296 keV, $\delta =-\left(6_{-1\mathrm{}}^{+3\mathrm{}}\right)$; 308 keV, $\delta =-(7.1\mathrm{}\pm 0.6)$; 417 keV, $\delta =4_{-3\mathrm{}}^{+7\mathrm{}}$; 485 keV, $\delta =5.8\mathrm{}\pm 0.8$; 604 keV, $\delta =1.5\mathrm{}\pm 0.1$, following the Rose-Brink sign convention. The angular distribution of the 672-keV $\beta$ group and the above $\gamma$ measurements limit the relative contribution, $I_L$, of different operator tensor ranks, $L$, involved in each $\beta$ transition. The results for electron-capture transitions terminating at levels in osmium are: 694-keV level, $I_1>0.9\mathrm{}$; 584-keV level, $I_0>0.6\mathrm{}$, $I_2<0.1\mathrm{}$. For $\beta$ transitions feeding platinum states, we determine: 921-keV level, $I_1>0.8\mathrm{}$; 785-keV level, $I_1>0.92\mathrm{}$, $I_2<0.03\mathrm{}$. The ${}_{}{}^{192}{}_{}{}^{}\mathrm{Ir}$ ground-state magnetic moment is determined to be positive.

Experimental results are reported on fission probabilities and fragment angular correlations for ($t, \mathrm{pf}$) reactions on ${}_{}{}^{230}{}_{}{}^{}\mathrm{Th}$, ${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}$, ${}_{}{}^{234}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{236}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{238}{}_{}{}^{}\mathrm{Pu}$, ${}_{}{}^{240}{}_{}{}^{}\mathrm{Pu}$, and ${}_{}{}^{242}{}_{}{}^{}\mathrm{Pu}$ targets. Systematic variations in the experimental results are used to qualitatively discuss properties of the fission barrier and low-lying transition-state spectra for these even-even nuclei.

$\gamma$ rays emitted in the radioactive decays of ${}_{}{}^{152}{}_{}{}^{}\mathrm{Eu}$ and ${}_{}{}^{154}{}_{}{}^{}\mathrm{Eu}$ have been studied with Ge(Li) and NaI detectors. Energies and relative intensities were derived from singles experiments with large volume Ge(Li) detectors and assignments of $\gamma$ rays to transitions in the level schemes were made with the help of Ge(Li)-NaI coincidence measurements. In all, 71 $\gamma$ rays were observed in the ${}_{}{}^{152}{}_{}{}^{}\mathrm{Eu}$ decay and 51 in the ${}_{}{}^{154}{}_{}{}^{}\mathrm{Eu}$ case. Three members of each of the $\beta$- and $\gamma$- vibrational bands were observed. In addition the results of the coincidence experiments are used to assign a level at 1649.8 keV as the probable $2^{-}$ member of the $K=2\mathrm{}$ band in ${}_{}{}^{152}{}_{}{}^{}\mathrm{Sm}$. The properties of this state and of the $K^{\pi }=0^{-} \mathrm{and} 1^{-}$ bands are compared with the properties of the corresponding states in ${}_{}{}^{154}{}_{}{}^{}\mathrm{Gd}$. It is found that there is evidently less Coriolis coupling between the negative-parity states in ${}_{}{}^{152}{}_{}{}^{}\mathrm{Sm}$ than in ${}_{}{}^{154}{}_{}{}^{}\mathrm{Gd}$. The members of the $K^{\pi }=1^{-}$ band in the former are not inverted as in the latter, and the $B\left(E1\mathrm{}\right)\mathrm{}$ ratios from the $K^{\pi }=0^{-}$ states in the former are in better agreement with the predictions of the rotational model. The low-energy levels in ${}_{}{}^{152}{}_{}{}^{}\mathrm{Gd}$ are considered in light of two possible interpretations. We find that it is preferable to consider these states as resulting from quasirotations and quasivibrations than to treat them as members of one-, two-, and three-phonon vibrational excitations about spherical equilibrium shapes. Finally, a new $2^{+}$ level at 1293 keV in ${}_{}{}^{152}{}_{}{}^{}\mathrm{Sm}$ is discussed in light of recent experiments involving two-neutron-transfer reactions to levels in this nucleus.

Einsteinium-253 nuclei were oriented at low temperatures in a neodymium ethylsulfate lattice. From the temperature-dependent $\alpha$-particle angular distribution a nuclear magnetic moment $\left|\mu \right|=(2.7\mathrm{}\pm 1.3){\mu }_N$ was deduced. From the values for the angular distribution function at the lowest temperatures it was possible to test the predictions of the Mang shell-model theory for the relative phases and amplitudes of the $\alpha$-partial waves. As predicted, the waves of angular momentum $L=0\mathrm{} \mathrm{and} 2$ are in phase, and the $L=0\mathrm{} \mathrm{and} 4$ waves are out of phase. The predicted wave amplitudes are in error, especially that of the $L=4\mathrm{}$ wave. The predicted relative intensities (which are proportional to the amplitudes squared) for the $S$, $D$, and $G$ waves are 1.000:0.179:0.0052, whereas the relative intensities that best fit the experimental angular distribution are 1.000:0.216:0.0078.

Excitation functions for $\gamma$-ray emission and cascade $\gamma$-ray emission following neutron inelastic scattering from the 0.93-, 1.39-, 1.50-, 1.84-, 2.05-, and 2.33-MeV levels of ${}_{}{}^{92}{}_{}{}^{}\mathrm{Zr}$ and the 0.913-, 1.30-, 1.66-, 2.06-, 2.16-, and 2.36-MeV levels of ${}_{}{}^{94}{}_{}{}^{}\mathrm{Zr}$ have been measured for neutrons in the energy range 0.9-2.69 MeV. Cascade $\gamma$ rays were detected with a sumcoincidence spectrometer consisting of two 3-in.-diam by 3-in.-long NaI(Tl) crystals each at 90° to the incident neutron beam direction. Crossover $\gamma$ rays and individual components of cascades were measured with a 4-${\mathrm{cm}}^3$ planar Ge(Li) detector. Multiple-scattering and beam-attenuation corrections were calculated analytically. Angular-correlation functions for the cascade $\gamma$ rays and angular distributions for the individual $\gamma$ rays were calculated and used to deduce total neutron inelastic scattering cross sections. These cross sections are in agreement with values calculated from Hauser-Feshbach theory corrected for level-width fluctuations and with previous measurements. The data support the tentative $J^{\pi }$ assignments of $2^{+}$ and $4^{+}$ for the 2.32- and 2.36-MeV levels of ${}_{}{}^{94}{}_{}{}^{}\mathrm{Zr}$, respectively, which resulted from recent ($p, p^{\prime }$) measurements.

The isotopic mass dispersion curves have been calculated by using a universal isobaric-charge dispersion function and the revised fission yield data for individual nuclides reported by Wahl et al. The mass dispersion curves are discontinuous at the most probable fragment mass value, so that a different dispersion curve applies on either side of the most probable mass, both branches being Gaussian, except at $Z=50\mathrm{}$ where the dispersion law deviates from the Gaussian in the region of mass numbers larger than the most probable mass. For some $Z$ values the dispersion is narrower on the light side and broader on the heavy side of the most probable mass, whereas the situation is the opposite for other $Z$ values, without apparent regularity. For a very few $Z$ values only, the two branches differ so little that they may practically be considered as defining a single curve.

Three $\alpha$ groups have been observed in the decay of the odd-odd nucleus ${}_{}{}^{240}{}_{}{}^{}\mathrm{Am}$ with energies and relative abundances of 5.378 (86.8%), 5.337 (12.0%), and 5.286 (1.23%) MeV. The branching ratio for these three $\alpha$ groups is 1.9×${10}^{-4\mathrm{}}$%. The ground state of ${}_{}{}^{240}{}_{}{}^{}\mathrm{Am}$ has spin and $K$ of 3, and odd parity. It is composed of proton and neutron quasiparticle states with Nilsson assignments ($K\pi \left[N{n}_z\Lambda \right]$) of $\frac{5}{2}$-[523] and ½+ [631], respectively. The most abundant $\alpha$ group is nearly unhindered, and hence the state it populates in ${}_{}{}^{236}{}_{}{}^{}\mathrm{Np}$ has the same configuration as the parent.

A detailed radiochemical investigation of the previously reported 5.3-h ${}_{}{}^{103}{}_{}{}^{}\mathrm{Mo}$ fission isomer was performed. The evidence obtained indicates that the reported fission activity is a misassignment and is probably due to contamination.

Irradiation of enriched ${}_{}{}^{150}{}_{}{}^{}\mathrm{Nd}$ with fast neutrons was found to produce a new radioactivity which was assigned to the ($n, p$) product ${}_{}{}^{150}{}_{}{}^{}\mathrm{Pr}$. The following radiation characteristics were observed to belong to ${}_{}{}^{150}{}_{}{}^{}\mathrm{Pr}$: half-life 6.1 ± 0.3 sec, $\gamma$-ray energy 131.0 ± 0.8 keV, and maximum ${\beta }^{-}$-ray energy 5.7 ± 0.3 MeV.

The isomer shifts of the 66.7-keV ${\frac{3}{2}}^{-}\to {\frac{1}{2}}^{-}$ and the 75.9-keV ${\frac{5}{2}}^{-}\to {\frac{1}{2}}^{-}$ $\gamma$ transitions of the ½[521] ground-state rotational band in ${}_{}{}^{171}{}_{}{}^{}\mathrm{Yb}$ have been investigated, using the Mössbauer effect. From the observed shifts, the ratio of change in mean square charge radii for the two excited states was found to be $\frac{\Delta 〈r^2〉\mathrm{}\left(76\right)\mathrm{}}{\Delta 〈r^2〉\mathrm{}\left(67\right)\mathrm{}}=+0.42\mathrm{}\pm \mathrm{0.20.}$ The decrease of $\Delta 〈r^2〉$ for higher rotational excitation is in disagreement with simple collective theory, and is discussed in terms of nonadiabatic effects.

From the observed magnetic hyperfine splitting, we also deduced the ratio of nuclear $g$ factors $\frac{g\left(76\right)\mathrm{}}{g\left(0\right)\mathrm{}}=+0.411\mathrm{}\pm \mathrm{0.002.}$ This value is in excellent agreement with an earlier measurement and has been used, together with other recent data on all magnetic parameters of the ½[521] band, in discussing the spin polarizations effects. The mixing ratio ${\delta }^2$ of the $\frac{M1\mathrm{}}{E2\mathrm{}}$, 66.7-keV $\gamma$ transition in ${}_{}{}^{171}{}_{}{}^{}\mathrm{Yb}$ was redetermined correcting carefully for finite absorber effects. The new result is ${\delta }^2=0.36\mathrm{}\pm \mathrm{0.04.}$

Low-spin states in ${\mathrm{Tl}}^{200}$ have been studied via the decay of 21.5-h ${\mathrm{Pb}}^{200}$, which was prepared by the reactions, ${\mathrm{Tl}}^{203}(p, 4n){\mathrm{Pb}}^{200}$, ${\mathrm{Hg}}^{202}(\tau , 5n){\mathrm{Pb}}^{200}$, and ${\mathrm{Tl}}^{203}(\tau , 6n){\mathrm{Bi}}^{200}\to {\mathrm{Pb}}^{200}$. Its $\gamma$ rays were studied in singles, coincidence, anticoincidence, and Ge(Li)-Ge(Li) two-dimensional (2048 × 2048 channel) coincidence experiments. Nineteen $\gamma$ transitions have been assigned to the decay of ${\mathrm{Pb}}^{200}$, and all have been placed in a consistent level scheme, States in ${\mathrm{Tl}}^{200}$ populated by ${\mathrm{Pb}}^{200}$ decay lie at 0 ($I\pi =2-$), 147.63 (0-), 257.19 (1-), 289.24 (2-, 1-) 289.92 (1-), 450.56 (1-), 525.54 (1-), and 605.44 keV (1-). Our spin and parity assignments are based on measured conversion coefficients, relative photon intensities, and $log\mathrm{ft}$ values. The structures of the states are discussed in terms of the coupling of the possible single-particle states in adjacent odd-$A$ nuclei. We also place an upper limit of 1 sec on the half-life of any possible isomeric state in ${\mathrm{Pb}}^{200}$ itself.

The off-shell continuation of the two-body $T$ matrix is written in terms of a $T$ matrix that is correct on-shell plus a term that effects only the off-shell behavior. The work of Baranger et al. and of Haftel is used to show what is arbitrary in the off-shell term for fixed on-shell data.

The energies and relative intensities of $\gamma$ rays emitted in the decay of ${}_{}{}^{81}{}_{}{}^{}\mathrm{Rb}$ have been measured for mass-separated sources using a 15-${\mathrm{cm}}^3$ Ge(Li) detector. New weak-intensity $\gamma$-rays have been observed at 244, 1041, 1069, 1109, 1429, and 1555 keV. The half-life of ${}_{}{}^{81}{}_{}{}^{}\mathrm{Rb}$ has been measured as 4.580±0.009 h.

Intrinsic quadrupole moments for the self-consistent deformed Hartree-Fock-Bogoliubov (HFB) shapes for the even Ti, Cr, and Fe isotopes are calculated and compared with results obtained from the self-consistent Hartree-Fock (HF) approximation. It is pointed out that in the HFB approximation for even $Z<N=28\mathrm{}$ nuclei one gets spherical shapes, and hence to calculate the $B\left(E_2\right)$ rates it is not proper to use the deformed HF wave functions. We calculate the $B\left(E_2\right)$ rates with the excited-state wave functions constructed over the spherical BCS solutions in the random-phase approximation.

More information on $B\left(M1\mathrm{}\right)\mathrm{}$ and $B\left(E2\mathrm{}\right)\mathrm{}$ values for $1^{+}$ and $3^{+}$ states in even nickel isotopes is made available. Results of calculations carried out with the Tabakin reaction matrix elements are also reported. The calculations are performed within the framework of the modified Tamm-Dancoff approximation.

Holm and Greiner have shown the effect of nuclear diffuseness on the barrier against fusion of two heavy nuclei. We show that the major part of this effect is a lowering of the barrier because of the diffuseness alone. There is an additional change in the barrier, due to deformation effects, which may be either positive or negative depending on the relative importance of the Coulomb and nuclear parts of the potential.