Employing the unitary-model approach of Shakin, Waghmare, Tomaselli, and Hull, and a modified version of the Yale potential, adjusted to yield a lower percentage of the "$D$" state in the deuteron ground state without affecting the other two-nucleon quantities calculable from the Yale potential, the ground-state properties of the even-even $N=Z$ nuclei are calculated for the $2s-1d$ shell by using the Hartree-Fock self-consistent approach. The healing distance for the relative ${}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}$ state is not used as a parameter since healing is "naturally" achieved for this state. Using the same values of the oscillator and level-shift parameters, the modified Yale interaction with its reduced tensor force component yields binding energies, single-particle energies, rms radii, and deformations which are generally closer to the experimental values than those reported for the Yale potential.

[NUCLEAR STRUCTURE ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$, ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$, ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$, ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$, ${}_{}{}^{36}{}_{}{}^{}\mathrm{A}$, ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$; calculated single-particle energies, ground-state energies, rms radii, and ground-state deformations. Hartree-Fock method. Modified Yale interaction.]

We have determined the half-lives of nuclides ${}_{}{}^{28}{}_{}{}^{}\mathrm{Mg}$, ${}_{}{}^{52}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{55}{}_{}{}^{}\mathrm{Co}$, ${}_{}{}^{57}{}_{}{}^{}\mathrm{Ni}$, ${}_{}{}^{67}{}_{}{}^{}\mathrm{Cu}$, ${}_{}{}^{69}{}_{}{}^{}\mathrm{Zn}_{}^m{}_{}{}^{}$, ${}_{}{}^{112}{}_{}{}^{}\mathrm{Pd}$, ${}_{}{}^{105}{}_{}{}^{}\mathrm{Ag}$, and ${}_{}{}^{111}{}_{}{}^{}\mathrm{Ag}$. The decay was followed for more than 10 half-lives in most cases. The long duration of the measurements, the stability of the counting equipment, and computer programs that allowed least-squares fitting to the sum of several exponentials yielded highly accurate values of the half-lives.

[RADIOACTIVITY ${}_{}{}^{28}{}_{}{}^{}\mathrm{Mg}$, ${}_{}{}^{52}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{55}{}_{}{}^{}\mathrm{Co}$, ${}_{}{}^{57}{}_{}{}^{}\mathrm{Ni}$, ${}_{}{}^{67}{}_{}{}^{}\mathrm{Cu}$, ${}_{}{}^{69}{}_{}{}^{}\mathrm{Zn}_{}^m{}_{}{}^{}$, ${}_{}{}^{112}{}_{}{}^{}\mathrm{Pd}$, ${}_{}{}^{105}{}_{}{}^{}\mathrm{Ag}$, ${}_{}{}^{111}{}_{}{}^{}\mathrm{Ag}$; measured $T_{\frac{1}{2}}$.]

The low-lying levels ${}_{}{}^{208}{}_{}{}^{}\mathrm{Po}$ have been calculated by a two-step shell-model calculation which uses the vector-coupled states from ${}_{}{}^{206}{}_{}{}^{}\mathrm{Pb}$ and ${}_{}{}^{210}{}_{}{}^{}\mathrm{Po}$ as a basis. The calculated and experimental energy levels are in good agreement with each other.

[NUCLEAR STRUCTURE ${}_{}{}^{208}{}_{}{}^{}\mathrm{Po}$; two-step shell model, calculated levels, $J$, $\pi$.]

Calculations similar to those previously used for a spherical nucleus were performed at various deformations ranging in some cases from $\delta =-0.5\mathrm{}$ to $\delta =1.0\mathrm{}$. The states for each spin projection ($K$) were ordered according to energy to avoid crossing of states with same spin projection and parity. The corresponding energies of the ordered sets for each deformation were considered as the energy vs deformation for particular states. Energies at intermediate deformations were obtained using a cubic interpolation. Energy minima and their associated deformations were determined for each state. States often have more than one energy minimum indicating the presence of shape isomers as illustrated in the cases of ${}_{}{}^{166}{}_{}{}^{}\mathrm{Ho}$ and ${}_{}{}^{240}{}_{}{}^{}\mathrm{Pu}$. In the former, a prolate and an oblate minimum exist which persist at higher energies. In the latter, a second prolate minimum is observed where the fission isomer is expected. Differences in energy gaps are discernible in the various minima. A plot of the deformations corresponding to the energy minima of the lowest energy states for each spin projection (the yrast levels) vs the spin projection reveals that the model nucleus becomes more oblate as the spin projection increases. The change in oblateness contains discontinuities. A plot of these yrast deformations vs the yrast energies for various nuclides indicates an apparent independence of the kind or size of the nuclide. The "best" $G$'s (pairing parameters) for some nuclides were determined by fitting the level densities to the experimental values at the neutron binding energies. The results for deformed nuclei are compared with the earlier results obtained for spherical nuclei.

[NUCLEAR STRUCTURE ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, ${}_{}{}^{114}{}_{}{}^{}\mathrm{Cd}$, ${}_{}{}^{166}{}_{}{}^{}\mathrm{Ho}$, ${}_{}{}^{240}{}_{}{}^{}\mathrm{Pu}$; calculated levels vs spin projection and deformation, yrast levels, deduced pairing parameters. Nilsson levels, BCS pairing.]

The 184.5-keV transition from the 1153.6-keV level of ${}_{}{}^{228}{}_{}{}^{}\mathrm{Th}$ excited in the decay of ${}_{}{}^{228}{}_{}{}^{}\mathrm{Ac}$ is shown to be (93±2)% $E0\mathrm{}$ in character from $\frac{K}{L}$ and $\frac{L_1}{L_{11}}$ conversion ratios. The half-life of the 1153.6-keV level is measured to be $T_{\frac{1}{2}}=0.29\mathrm{}\pm 0.02$ ns from $\beta -\gamma$ delayed coincidence measurements. From this, the value of the monopole strength parameter is deduced to be $\rho =0.11\mathrm{}\pm 0.02$.

[RADIOACTIVITY ${}_{}{}^{288}{}_{}{}^{}\mathrm{Ac}$ measured $I_{\mathrm{ce}}$; $\beta -\gamma$ delay; levels in ${}_{}{}^{228}{}_{}{}^{}\mathrm{Th}$; deduced $\gamma$ multipolarity $T_{\frac{1}{2}}$.]

The $L$-shell internal-ionization probability accompanying $K$ capture, $K$-shell internal-ionization probability accompanying $L$ capture, and the ejected-electron spectrum during these processes have been calculated using screened relativistic hydrogenic wave functions. The screening constant for the daughter atom is determined taking into account the presence of a vacancy resulting from electron capture. The results show that $L$-shell contributions are important for the low-energy region of the electron spectrum and for high -$Z$ elements. It is also concluded that the presence of a vacancy in the inner shell of the daughter atom plays an important role.

[RADIOACTIVITY ${}_{}{}^{37}{}_{}{}^{}\mathrm{Ar}$, ${}_{}{}^{55}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{71}{}_{}{}^{}\mathrm{Ge}$, ${}_{}{}^{131}{}_{}{}^{}\mathrm{Cs}$, ${}_{}{}^{165}{}_{}{}^{}\mathrm{Er}$; calculated internal-ionization probability accompanying EC, ejected-electron spectrum.]

The $L$-shell internal ionization accompanying $L$ capture has been considered. Numerical calculations of the internal-ionization probabilities per $L$ capture and the energy spectra of electrons ejected during this process are presented for low-energy transitions in high-$Z$ elements. Screened relativistic hydrogenic wave functions are used. The effect of the presence of a hole resulting from electron capture is included in the screening constant for the daughter atom. It is shown that the ionization probability per $L$ capture depends upon $\frac{B_i}{E_0}$, where $E_0$ is the transition energy of the ordinary electron capture and $B_i$ is the $L_i$-shell binding energy of the daughter atom ($i=1,2,3\mathrm{}$). The calculated results also predict that observation of this process is possible when the $K$-shell internal-ionization process during $K$ capture is forbidden energetically. Possible experiments to detect this phenomenon are briefly discussed.

[RADIOACTIVITY ${}_{}{}^{157}{}_{}{}^{}\mathrm{Tb}$, ${}_{}{}^{179}{}_{}{}^{}\mathrm{Ta}$, ${}_{}{}^{193}{}_{}{}^{}\mathrm{Pt}$; calculated $L$-shell internal-ionization probability accompanying $L$-shell EC, ejected-electron spectrum.]

Evidence of configuration mixing of higher-$K$ bands in deformed even nuclei is surveyed. A general formulation for configuration mixing due to a two-body neutron-proton force is developed. A fit to the energy splittings of Gallagher-Moszkowski pairs in odd-odd nuclei is made to obtain an effective Gaussian central force except for the undetermined Wigner component. With this force, off-diagonal band-mixing matrix elements are calculated for various configurations in ${}_{}{}^{176}{}_{}{}^{}\mathrm{Hf}$, ${}_{}{}^{178}{}_{}{}^{}\mathrm{Hf}$, and ${}_{}{}^{174}{}_{}{}^{}\mathrm{Yb}$. By solving BCS equations, the relevant occupation amplitudes are calculated. The effective $n-p$ Wigner force component is fixed to give best over-all agreement to experimental band-mixing information. The resulting force is compared with the Jones, Onishi, Hess, and Sheline central force for deformed nuclei.

[NUCLEAR STRUCTURE ${}_{}{}^{174,176,178,180}{}_{}{}^{}\mathrm{Hf}$, ${}_{}{}^{174}{}_{}{}^{}\mathrm{Yb}$; calculated configuration mixing higher $K$ bands, fit energy splittings, Gallagher-Moszkowski pairs, $n-p$ force deduced.]

A generalization of the classical semimicroscopic model is developed to explain simultaneously quasivibrational and quasirotational nuclear states. The wave functions obtained are used to calculate level sequences, electromagnetic properties, and spectroscopic factors. Experimental data are reasonably well fitted.

[NUCLEAR STRUCTURE ${}_{}{}^{115,117}{}_{}{}^{}\mathrm{In}$; calculated levels, $J$, $\pi$, $B\left(E2\mathrm{}\right)\mathrm{}$, $B\left(M1\mathrm{}\right)\mathrm{}$, $q$, $\mu$, and $S$. Generalized semimicroscopic model.]

The $\gamma$-ray decay of 64-sec fission-product ${}_{}{}^{140}{}_{}{}^{}\mathrm{Cs}$ has been studied using the TRISTAN on-line isotope-separator system. Ge(Li) detector singles and Ge(Li)-Ge(Li) coincidences were performed. 154 $\gamma$-ray transitions were assigned to a level scheme for ${}_{}{}^{140}{}_{}{}^{}\mathrm{Ba}$ with 30 definite and 13 tentative excited levels. Tentative spin and parity assignments were made for some of these levels. The relationship between ${}_{}{}^{140}{}_{}{}^{}\mathrm{Ba}$ and the other even Ba isotopes is discussed, and an interesting similarity with ${}_{}{}^{134}{}_{}{}^{}\mathrm{Ba}$ is noted.

[RADIOACTIVITY ${}_{}{}^{140}{}_{}{}^{}\mathrm{Cs}$ (from ${}_{}{}^{140}{}_{}{}^{}\mathrm{Xe}$ decay); measured $E_{\gamma }$, $I_{\gamma }$, $\gamma -\gamma$ coin, deduced $log\mathrm{ft}$. ${}_{}{}^{140}{}_{}{}^{}\mathrm{Ba}$ deduced levels, $J$, $\pi$. Mass-separated ${}_{}{}^{140}{}_{}{}^{}\mathrm{Xe}$ activity.]

The ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}\mathrm{}(p,d)\mathrm{}{}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$ reaction to the $3p_{\frac{1}{2}}$, $2f_{\frac{5}{2}}$, and $3p_{\frac{3}{2}}$ single-hole states was studied at energies below the Coulomb barrier. The ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}\mathrm{}(d,t)\mathrm{}{}_{}{}^{47}{}_{}{}^{}\mathrm{Ca}$ reaction to the $1f_{\frac{7}{2}}$ single-hole state was studied near the Coulomb barrier. Distorted-wave Born-approximation analyses provided values for the root-mean-square radii of the orbitals of the picked-up neutrons. These values are in agreement with results obtained from other reactions and from nuclear-structure calculations, but disagree with values based on analyses of Coulomb displacement energies.

[NUCLEAR REACTIONS ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}\mathrm{}(p,d)\mathrm{}$, $E=12\mathrm{}$ MeV; measured $\sigma (E_d,\theta )$. ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}(d,t_0)$, $E=7.3\mathrm{}$ MeV; measured $\sigma \left(\theta \right)$. Deduced rms radii for picked-up neutrons. Comparisons with Coulomb displacement energies.]

An $E1+E3\mathrm{}$ ($\le 1.9\% M2\mathrm{}$) multipole mixture has been observed for the 1242-keV ($2^{-}$ → $2^{+}$) transition depopulating the $J^{\pi }$, $K=2^{-},2\mathrm{}$ octupole vibrational level at 1318 keV in ${}_{}{}^{174}{}_{}{}^{}\mathrm{Yb}$ following the decay of ${}_{}{}^{174}{}_{}{}^{}\mathrm{Lu}$ and ${}_{}{}^{174}{}_{}{}^{}\mathrm{Lu}_{}^m{}_{}{}^{}$. The internal-conversion cœfficient for this transition and the $\gamma -\gamma$ directional correlation for the 1242-76.5-keV cascade have been remeasured, and the results yield the unique set of multipole mixing ratios ${\delta }_1\left(\frac{M2\mathrm{}}{E1\mathrm{}}\right)=0.05\mathrm{}\pm 0.09$ and ${\delta }_2\left(\frac{E3\mathrm{}}{E1\mathrm{}}\right)=0.19\mathrm{}\pm 0.08$ which correspond to a multipole admixture of $E1({96.3}_{-2.6\mathrm{}}^{+1.7\mathrm{}}\%)+M2({0.2}_{-0.2\mathrm{}}^{+1.7\mathrm{}}\%)+E3({3.5}_{-2.1\mathrm{}}^{+3.8\mathrm{}}\%)$. The $M2\mathrm{}$ multipolarity of the 1318-keV ($2^{-}$ → $0^{+}$) transition was also verified from the measured internal-conversion coefficient. A multipole admixture of $E3\mathrm{}$ ($<27\% M2\mathrm{}$) for the 1065-keV transition was deduced from available data, and the ratios of reduced transition probabilities for the transitions depopulating the 1318-keV level were calculated and compared with rotational-model predictions. Using the previously measured half-life of the $2^{-}$ level, absolute transition probabilities and hindrance factors were obtained for these transitions, and $B\left(E3\mathrm{}\right)\mathrm{}$ values were compared with theoretical microscopic model calculations. Partial correlation coefficients for the 992-keV transition depopulating the 1518-keV isomeric state were determined using the $\gamma -\gamma$ directional correlation data. Multipole admixtures consistent with the correlation data (and internal conversion data for the $7^{-}$ case) are $E2+(27\mathrm{}\pm 8\%)M1$ for the choice of $6^{+}$ and $E1(68\mathrm{}\pm 7\%)+M2(5\pm 2\%)+E3(27\pm 7\%)$ for the choice of $7^{-}$ for the 1518-keV level. Using the reported half-life for that level, the hindrance factors were obtained for the $K$-forbidden transitions depopulating the level for each choice of spin assignment and these are compared with hindrance factors observed for known $K$-forbidden transitions.

[RADIOACTIVITY ${}_{}{}^{174}{}_{}{}^{}\mathrm{Lu}$ [from ${}_{}{}^{174}{}_{}{}^{}\mathrm{Yb}\mathrm{}(d,2n)\mathrm{}$] measured $I_{\gamma }$, $\gamma \gamma \left(\theta \right)$, $I \left(\mathrm{ce}\right)$; deduced $J$, $\pi$, ICC, $\gamma$ mixing, $B\left(E3\mathrm{}\right)\mathrm{}$.]

An 89-keV $\gamma$ line has recently been observed in ${}_{}{}^{99}{}_{}{}^{}\mathrm{Tc}$ and attributed to a weak (1.6×${10}^{-5\mathrm{}}$) $\beta$ branch leading to the 89-keV level in ${}_{}{}^{99}{}_{}{}^{}\mathrm{Ru}$. However, the long ${}_{}{}^{99}{}_{}{}^{}\mathrm{Tc}$ lifetime makes it difficult to be sure such a $\gamma$ line is not due to a long-lived contaminant. We have observed the 89-keV transition and measured the half-life of the state feeding it, using the delayed coincidence method: The result (18.9±1.0 nsec) agrees with measurements of the lifetime of the ${}_{}{}^{99}{}_{}{}^{}\mathrm{Ru}$ 89-keV state. The $\beta$ group in coincidence with the 89-keV $\gamma$ line also shows an end-point energy about 89 keV less than that of the ground-state group. These results confirm the existence of the proposed weak $\beta$ branch, for which we find a branching ratio of (1.2±0.4)×${10}^{-5\mathrm{}}$.

[RADIOACTIVITY ${}_{}{}^{99}{}_{}{}^{}\mathrm{Tc}$; measured $E_{\gamma }$, $\beta \gamma$ coin, $E_{\beta }$; deduced $\beta$ branching ratio to 89-keV level in ${}_{}{}^{99}{}_{}{}^{}\mathrm{Ru}$.]

The $\gamma$-ray spectrum from neutron capture in the 9.47-eV resonance in ${}_{}{}^{129}{}_{}{}^{}\mathrm{Xe}$ has been studied. A target of ${\mathrm{Na}}_4$Xe${\mathrm{O}}_6$ was irradiated in a thermal neutron beam and in a monochromatic neutron beam of 5.16-, 9.47-, and 14.1-eV energy from a crystal diffraction neutron monochromator. The resulting $\gamma$-ray spectra were studied with Ge(Li) detectors of $\simeq 20$-, $\simeq 25$-, $\simeq 30$-, and $\simeq 40$-${\mathrm{cm}}^3$ active volume. $\gamma$ rays were assigned to the ${}_{}{}^{129}{}_{}{}^{}\mathrm{Xe}\left(n \gamma \right){}_{}{}^{130}{}_{}{}^{}\mathrm{Xe}$ reaction by a comparison of these spectra. Ge(Li)-Ge(Li) coincidence measurements were carried out on resonance with the 20- and 30-${\mathrm{cm}}^3$ Ge(Li) detectors in combination. Only a few very intense transitions were observed in coincidence. The data obtained in the present work together with the information from earlier radioactive-decay studies indicate the population of levels in ${}_{}{}^{130}{}_{}{}^{}\mathrm{Xe}$ by neutron capture in the 9.47-eV resonance with energies 536.1 ± 0.2, 1122.1 ± 0.3, 1204.4 ± 0.5, 1631.8 ± 0.7, 1785.9 ± 0.8, 1792.1 ± 0.6, 1807.9 ± 0.4, 2017.0 ± 0.5, 2058.7 ± 0.9, 2081.4 ± 0.9, 2171.0 ± 1.3, 2222.6 ± 0.6, 2241.5 ± 0.6, 2385.1 ± 0.5, 2501.9 ± 0.5, 2544.4 ± 0.9, 2632.4 ± 1.7, (2762.7 ± 0.5), 2885.6 ± 1.1, 2953.5 ± 0.5, 2977.5 ± 1.0, 3071.1 ± 0.8, 3150.1 ± 0.7, 3188.8 ± 0.6, (3243.2 ± 1.3), 3298.0 ± 1.2, 3325.1 ± 0.8, 3405.2 ± 0.7, 3534.2 ± 0.6, 3621.9 ± 0.7, 3685.6 ± 1.0, 3780.0 ± 1.2, 3892.2 ± 1.5, (3960.1 ± 1.0), 3976.3 ± 1.5, and 3985.6 ± 1.0 keV. The neutron separation energy of ${}_{}{}^{130}{}_{}{}^{}\mathrm{Xe}$ is 9254.7 ± 1.3 keV. The observation of the 9254.2 ± 2.1 keV primary-capture $\gamma$ ray to the 0+ ground state of ${}_{}{}^{130}{}_{}{}^{}\mathrm{Xe}$ clearly establishes the spin of the 9.47-eV resonance in ${}_{}{}^{129}{}_{}{}^{}\mathrm{Xe}$ as 1+.

[NUCLEAR REACTIONS ${}_{}{}^{129}{}_{}{}^{}\mathrm{Xe}(n,\gamma )$, $E=9.47\mathrm{}$ eV; measured $E_{\gamma }$, $I_{\gamma }$, $\gamma -\gamma$ coin. in ${}_{}{}^{130}{}_{}{}^{}\mathrm{Xe}$. ${}_{}{}^{130}{}_{}{}^{}\mathrm{Xe}$ deduced levels, transitions, $Q$, $J$, $\pi$.]

The $\gamma$-ray transitions following the decay of 9.2-min ${}_{}{}^{130}{}_{}{}^{}\mathrm{I}_{}^m{}_{}{}^{}$ have been measured using Ge(Li) Compton-suppressed $\gamma$-ray spectrometry. Three new levels in ${}_{}{}^{130}{}_{}{}^{}\mathrm{Xe}$ have been proposed at 2762.6, 2644.9, and 2307.8 keV and new $\beta$ branches observed to four levels at 1632.6, 2385.5, 2544.4, and 2637.5 keV. The results are compared with those of other recent studies and the difficulties of finding an adequate theoretical description discussed.

[RADIOACTIVITY ${}_{}{}^{130}{}_{}{}^{}\mathrm{I}_{}^m{}_{}{}^{}$ from ${}_{}{}^{129}{}_{}{}^{}\mathrm{I}(n,\gamma )$. Measured $E_{\gamma }$, $I_{\gamma }$. ${}_{}{}^{130}{}_{}{}^{}\mathrm{Xe}$, deduced levels, $E_{\beta }$, $I_{\beta }$, $J$, $\pi$. Enriched target. Ge(Li) detector.]

Differential cross sections for elastic scattering of 7.9-MeV photons from ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$ have been measured at angles ranging from 25 to 140°. These results and previously measured differential cross sections from ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ and ${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}$ are compared with theoretical predictions taking into account Rayleigh scattering, nuclear Thomson scattering, nuclear resonance scattering, and Delbruck scattering. It is shown that at this energy the forward elastic scattering at angles ≤75° is due almost entirely to Delbruck scattering. The experimental results were found to deviate systematically from predicted values throughout most of the angular range. A striking agreement with theory was obtained only after excluding the contribution of the real part of the Delbruck scattering amplitude.

[NUCLEAR REACTIONS ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}(\gamma ,\gamma )$, $E=7.9\mathrm{}$ MeV; measured Delbruck scattering, $\sigma \left(\Theta \right)$, $\Theta =25-{140}^{\circ }$.]

From coincidence measurements on $\gamma -\gamma$ cascades following the decay of ${}_{}{}^{129}{}_{}{}^{}\mathrm{Te}_{}^m{}_{}{}^{}$ the existence of a 1047-keV level in ${}_{}{}^{129}{}_{}{}^{}\mathrm{I}$ is well established. Angular correlation measurements for several cascades give the following values: $\{281-251-\mathrm{k}\mathrm{e}\mathrm{V}\mathrm{c}\mathrm{a}\mathrm{s}\mathrm{c}\mathrm{a}\mathrm{d}\mathrm{e}:,A_{22}= 0.238\pm 0.015,,A_{44}= 0.014\pm 0.026;\}\{209-251-\mathrm{k}\mathrm{e}\mathrm{V}\mathrm{c}\mathrm{a}\mathrm{s}\mathrm{c}\mathrm{a}\mathrm{d}\mathrm{e}:,A_{22}= 0.234\pm 0.012,,A_{44}= 0.011\pm 0.022;\}\{281-278-\mathrm{k}\mathrm{e}\mathrm{V}\mathrm{c}\mathrm{a}\mathrm{s}\mathrm{c}\mathrm{a}\mathrm{d}\mathrm{e}:,A_{22}=-0.048\mathrm{}\pm 0.014,,A_{44}=-0.014\mathrm{}\pm 0.023;\}\{209-278-\mathrm{k}\mathrm{e}\mathrm{V}\mathrm{c}\mathrm{a}\mathrm{s}\mathrm{c}\mathrm{a}\mathrm{d}\mathrm{e}:,A_{22}=-0.059\mathrm{}\pm 0.011,,A_{44}= 0.018\pm 0.018;\}\{624-209-\mathrm{k}\mathrm{e}\mathrm{V}\mathrm{c}\mathrm{a}\mathrm{s}\mathrm{c}\mathrm{a}\mathrm{d}\mathrm{e}:,A_{22}=-0.270\mathrm{}\pm 0.065,,A_{44}= 0.047\pm 0.095;\}\{624-460-\mathrm{k}\mathrm{e}\mathrm{V}\mathrm{c}\mathrm{a}\mathrm{s}\mathrm{c}\mathrm{a}\mathrm{d}\mathrm{e}:,A_{22}= 0.151\pm 0.009,,A_{44}= 0.003\pm 0.012;\}\{624-478-\mathrm{k}\mathrm{e}\mathrm{V}\mathrm{c}\mathrm{a}\mathrm{s}\mathrm{c}\mathrm{a}\mathrm{d}\mathrm{e}:,A_{22}=-0.290\mathrm{}\pm 0.025,,A_{44}=-0.002\mathrm{}\pm 0.036;\}\{343-460-\mathrm{k}\mathrm{e}\mathrm{V}\mathrm{c}\mathrm{a}\mathrm{s}\mathrm{c}\mathrm{a}\mathrm{d}\mathrm{e}:,A_{22}=-0.341\mathrm{}\pm 0.058,,A_{44}= 0.033\pm \mathrm{0.080.}\}$ These values, together with nuclear orientation data, uniquely determine the spin of the excited states at 278 keV ($\frac{3}{2}$) and 860 keV ($\frac{3}{2}$). The mixing ratios $\delta \left(\frac{E2\mathrm{}}{M1\mathrm{}}\right)$ for the different transitions are obtained.

[RADIOACTIVITY ${}_{}{}^{129}{}_{}{}^{}\mathrm{Te}$ from ${}_{}{}^{128}{}_{}{}^{}\mathrm{Te}(n,\gamma )$; measured $\gamma \gamma$ coin, $\gamma \gamma \left(\theta \right)$. ${}_{}{}^{129}{}_{}{}^{}\mathrm{I}$ deduced levels, $J$, $\gamma$-mixing ratios. Enriched target, Ge(Li), Na(Tl) detectors.]

The ion-implantation-perturbed-angular-correlation technique has been used to measure the Larmor precessions of the first $2^{+}$ excited states of ${}_{}{}^{182,184,186}{}_{}{}^{}\mathrm{W}$ in a ferromagnetic nickel host. The observed angular precessions, corrected for the transient field effect, were $\omega {\tau }_{182}\left(2^{+}\right)=0.159\mathrm{}\pm 0.003$ rad, $\omega {\tau }_{184}\left(2^{+}\right)=0.156\mathrm{}\pm 0.011$ rad, and $\omega {\tau }_{186}\left(2^{+}\right)=0.160\mathrm{}\pm 0.007$ rad. Use is made of the accepted $g$ factor of ${}_{}{}^{184}{}_{}{}^{}\mathrm{W}$, $g_{184}\left(2^{+}\right)=0.288\mathrm{}\pm 0.007$, to obtain $H_{\mathrm{hf}}(Ni-\mathrm{W})=(-67\mathrm{}\pm 5)$ kOe at 305 K. The $g$ factors of ${}_{}{}^{182,186}{}_{}{}^{}\mathrm{W}$, determined relative to the known $g$ factor of ${}_{}{}^{184}{}_{}{}^{}\mathrm{W}$, are $g_{182}\left(2^{+}\right)=0.271\mathrm{}\pm 0.021$, and $g_{186}\left(2^{+}\right)=0.370\mathrm{}\pm 0.036$. Larmor precessions were also measured for the first $2^{+}$ excited states of ${}_{}{}^{184,186}{}_{}{}^{}\mathrm{W}$ in a ferromagnetic cobalt host. The corrected observed angular precessions were $\omega {\tau }_{184}\left(2^{+}\right)=0.839\mathrm{}\pm 0.019$ and $\omega {\tau }_{186}\left(2^{+}\right)=0.833\mathrm{}\pm 0.015$. The resulting hyperfine field on tungsten in cobalt, assuming $g_{184}\left(2^{+}\right)=0.288\mathrm{}\pm 0.007$, is $H_{\mathrm{hf}}(Co-\mathrm{W})=(-341\mathrm{}\pm 12)$ kOe, and the resulting $g$ factor of the first excited state of ${}_{}{}^{186}{}_{}{}^{}\mathrm{W}$, determined relative to $g_{184}\left(2^{+}\right)$ in the cobalt host, is $g_{186}\left(2^{+}\right)=0.358\mathrm{}\pm 0.021$. Agreement between $g_{186}\left(2^{+}\right)$ obtained from using a nickel host and $g_{186}\left(2^{+}\right)$ obtained using a cobalt host was very good, and a weighted average of these two independent measurements gives $g_{186}\left(2^{+}\right)=0.361\mathrm{}\pm 0.018$. Target temperature measurements as a function of beam current were also performed. The observed trend of $g$ with increasing $A$ is not compatible with present theories.

[NUCLEAR REACTIONS ${}_{}{}^{182,184,186}{}_{}{}^{}\mathrm{W}({}_{}{}^{16}{}_{}{}^{}\mathrm{O},{}_{}{}^{16}{}_{}{}^{}\mathrm{O}_{}^{\prime }{}_{}{}^{}\gamma )$, $E=36\mathrm{}$ MeV; measured ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}\gamma$-coin, $\gamma \gamma (\theta ,\mathrm{H})$ in Ni, Co; deduced hyperfine fields. NUCLEAR MOMENTS ${}_{}{}^{182,184,186}{}_{}{}^{}\mathrm{W}$; deduced $g$ for 100, 111, 123 keV levels.]

Coulomb excitation experiments on ${}_{}{}^{152}{}_{}{}^{}\mathrm{Sm}$ and ${}_{}{}^{162}{}_{}{}^{}\mathrm{Dy}$ by 48 MeV ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ particles were performed at 110, 120, and 140° with 50 keV energy resolution. The $B(E2,2^{+}\to 4^{+})$ and the reduced $E2\mathrm{}$ matrix element $〈4^{+}\parallel \mathfrak{M}\mathrm{}\left(E2\mathrm{}\right)\mathrm{}\parallel 4^{+}〉$ were deduced from the excitation probabilities by using the quantum-mechanical coupled-channels code AROSA. The results are: $B(E2,2^{+}\to 4^{+})=1.87\mathrm{}\pm 0.13 e^2{\mathrm{b}}^2$ $〈4^{+}\parallel \mathfrak{M}\mathrm{}\left(E2\mathrm{}\right)\mathrm{}\parallel 4^{+}〉=-3.4\mathrm{}\pm 1.9 e\mathrm{b}$ for ${}_{}{}^{152}{}_{}{}^{}\mathrm{Sm}$, and for ${}_{}{}^{162}{}_{}{}^{}\mathrm{Dy}$ $B(E2,2^{+}\to 4^{+})=2.93\mathrm{}\pm 0.20 e^2{\mathrm{b}}^2$, $〈4^{+}\parallel \mathfrak{M}\mathrm{}\left(E2\mathrm{}\right)\mathrm{}\parallel 4^{+}〉=-5.5\mathrm{}\pm 3.6 e\mathrm{b}$. These values agree with the rigid rotator relation within the experimental uncertainties.

[NUCLEAR REACTIONS ${}_{}{}^{152}{}_{}{}^{}\mathrm{Sm}$, ${}_{}{}^{162}{}_{}{}^{}\mathrm{Dy}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$′), $E=48\mathrm{}$ MeV; measured $\left(\frac{d\sigma }{d\Omega }\right)\left(\theta \right)$, deduced $B(E2,2^{+}\to 4^{+})$, $〈4^{+}\parallel \mathfrak{M}\mathrm{}\left(E2\mathrm{}\right)\mathrm{}\parallel 4^{+}〉$.]

Energy dissipation during sliding contact is discussed as a fusion limiting mechanism in heavy-ion collisions. A simple model yields a critical angular momentum for fusion in good agreement with the experimental trend of Natowitz after normalization. Estimates of the nuclear viscosity coefficient are in order of magnitude agreement with two available values.

[NUCLEAR REACTIONS, HI fusion Limit calculated from surface friction model. Viscosity deduced from experimental data trend.]