The real part of the nucleus-nucleus potential is calculated by using a density-dependent effective interaction where the local density takes into account the contribution of both the projectile and the target densities. The results indicate that the repulsion produced by the density-dependent part of the interaction is important when the densities of the two nuclei overlap significantly but not so important at a distance much greater than the touching radius. For a quite heavy target-projectile system the repulsive term is important even in the tail region. The exchange effects have been found to be be not so important. The imaginary potential is approximately estimated by using a forward scattering amplitude approximation. The preliminary results agree with phenomenological predictions. The parameter ${\mathcal{r}}_C$ which determines the critical distance of approach both for the real and the imaginary potential, remains constant [${\mathcal{r}}_{C0\mathrm{}}\simeq 1.0=\frac{R_{C0\mathrm{}}}{({A_P}^{\frac{1}{3}}+{A_T}^{\frac{1}{3}})}$] throughout the Periodic Table.

NUCLEAR REACTIONS Calculated optical potential for two colliding nuclei using a density-dependent effective interaction and the forward scattering amplitude approximation for the imaginary potential.

Differential cross sections have been measured at a proton bombarding energy of 39.8 MeV for ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}(p, t)$ transitions to the $0_1^{+}$, $2_1^{+}$, and $4_1^{+}$ states of ${}_{}{}^{18}{}_{}{}^{}\mathrm{Ne}$ at 0.0, 1.89, and 3.38 MeV, respectively, and to the ($0_2^{+}$, $2_2^{+}$) doublet in ${}_{}{}^{18}{}_{}{}^{}\mathrm{Ne}$ at (3.58, 3.62) MeV. These cross sections are compared with zero-range coupled-channel Born-approximation calculations in which the coexistence-model wave functions of Benson and Flowers have been used. The inclusion of inelastic effects improves the agreement between experiment and theory; however, the calculated ($p, t$) cross sections are quite sensitive to the nature of the inelastic processes in the $t$+${}_{}{}^{18}{}_{}{}^{}\mathrm{Ne}$ channel, and, until these processes are better understood, it is not possible for the calculation to provide a sensitive test of the mass-18 nuclear wave functions used.

NUCLEAR REACTIONS ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}(p, t)$, $E=39.8\mathrm{}$ MeV; measured $\sigma \left(\theta \right)$ and calculated $\sigma \left(\theta \right)$ with CCBA and DWBA.

The formalism for the analysis of isospin mixing in the decay of compound nuclei has been reformulated to include "upward" mixing of the $T^{<}$ into the $T^{>}$ states as well as the usual "down-ward" mixing of $T^{>}$ into $T^{<}$. The ratio of isospin mixing parameters for these two processes, $\frac{{\mu }^{\uparrow }}{\mu }$, is evaluated for compound nuclei in the $A\sim 50-70$ region and is ∼ 0.03. The mixing matrix element has an average value of ∼ 70±40 eV in this mass region.

NUCLEAR REACTIONS Deduced Coulomb mixing matrix elements in the decay of ${}_{}{}^{49}{}_{}{}^{}\mathrm{V}$, ${}_{}{}^{52}{}_{}{}^{}\mathrm{Cr}$, ${}_{}{}^{55}{}_{}{}^{}\mathrm{Mn}$, ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{60}{}_{}{}^{}\mathrm{Ni}$, ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}$, ${}_{}{}^{64}{}_{}{}^{}\mathrm{Zn}$, ${}_{}{}^{66}{}_{}{}^{}\mathrm{Zn}$, ${}_{}{}^{69}{}_{}{}^{}\mathrm{Ga}$ at ∼ 20 MeV.

A total of 21 states of ${}_{}{}^{33}{}_{}{}^{}\mathrm{S}$ in the region of excitation from about 8.6 to 9.5 MeV have been studied using the reaction ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}(d, p)$ at 12 MeV incident deuteron energy and a biased quadrupole spectrometer. Fractionated single-particle states are identified via their forward-angle cross sections, using distorted-wave Born-approximation predictions with resonance state form factors for the residual ${}_{}{}^{33}{}_{}{}^{}\mathrm{S}$ system. Results are compared with those from ($n, n$) and/or ($n, \gamma$) studies over the same region of excitation, where this is possible. It is shown that states strongly populated in ($n, n$) do not often show up in ($d, p$) spectra and vice versa.

NUCLEAR REACTIONS ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}(d, p)$, $E_d=12\mathrm{}$ MeV, measured $\sigma \left(\theta \right)$. ${}_{}{}^{33}{}_{}{}^{}\mathrm{S}$ deduced levels, $l$, $j$, $\pi$, spectroscopic factors. DWBA analysis, resolution 12 keV; comparison to neutron total $\sigma$, ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$.

Strong $E2\mathrm{}$, $E3\mathrm{}$, $E4\mathrm{}$, and $E5\mathrm{}$ excitations of low-lying states in ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$ were observed in an electron scattering experiment. From the measured form factors the following radiative transition strengths to the ground state (in Weisskopf units) were extracted: ${\mathrm{}\left|M\right(E2\mathrm{}\left)\right|}^2=8.1\mathrm{}\pm 1.0$ (the 1.55-MeV ${\frac{3}{2}}^{+}$ state), 1.0±0.2 (4.56-MeV ${\frac{5}{2}}^{+}$); ${\mathrm{}\left|M\right(E3\mathrm{}\left)\right|}^2=11\mathrm{}\pm 3$ (1.35-MeV ${\frac{5}{2}}^{-}$), 15±4 (5.43-MeV ${\frac{7}{2}}^{-}$); ${\mathrm{}\left|M\right(E4\mathrm{}\left)\right|}^2=5.8\mathrm{}\pm 1.3$ (2.78-MeV ${\frac{9}{2}}^{+}$); and ${\mathrm{}\left|M\right(E5\mathrm{}\left)\right|}^2=16\mathrm{}\pm 7$ (4.03-MeV ${\frac{9}{2}}^{-}$). A fairly large transverse form factor was found for the 2.78-MeV ${\frac{9}{2}}^{+}$ state. The value of $B(M5, {\frac{9}{2}}^{+}\to \mathrm{g}.\mathrm{s}.\mathrm{})=(3.0\mathrm{}\pm 1.2)\times {10}^4{e}^2$ ${\mathrm{fm}}^{10}$ was extracted from the experimental data on the assumption that this transverse form factor resulted from $M5\mathrm{}$ excitation only. The experimental form factors and radiative transition strengths for positive-parity states are compared with theoretical values calculated using the rotation-particle coupling (RPC) model; good agreement is obtained for the states predominantly belonging to the ground-state band: the 0.197-MeV ${\frac{5}{2}}^{+}$, 1.55-MeV ${\frac{3}{2}}^{+}$, and 2.78-MeV ${\frac{9}{2}}^{+}$ states. It is found that RPC is essential, in particular, to the $E4\mathrm{}$ and $M5\mathrm{}$ transitions of the 2.78-MeV ${\frac{9}{2}}^{+}$ state. The $E3\mathrm{}$ transition strength of the 5.43-MeV ${\frac{7}{2}}^{-}$ state, as well as the 1.35-MeV ${\frac{5}{2}}^{-}$ state, is comparable with that of the octupole-vibrational state at 6.13 MeV in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$.

NUCLEAR REACTIONS ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}(e, e^{\prime })$, $E=134.5, 150, 250$ MeV; measured $\sigma (E ;\theta )$; deduced $B\left(\Lambda \right)$. ${\left(\mathrm{C}{\mathrm{F}}_2\right)}_n$ target. Compared with the rotation-particle coupling model.

We present a detailed evaluation of the leading term (triangle diagram) of the pion-nucleus optical potential. The development uses a covariant multiple scattering theory introduced previously. It is shown how recent phenomenological studies of the pion-nucleon (off-shell) scattering amplitudes may be incorporated into this theory. Further, various problems associated with the transformation of the pion-nucleon scattering amplitudes from the center of mass of the $\pi -N$ system to the center of mass of the $\pi$-nucleus system are resolved in this approach.

After qualitative discussion of what can be expected in quasielastic ($\pi , {\pi }^{\prime }$) experiments, a semiclassical model is developed. The mean free path for pion absorption in nuclear matter is a more or less unknown ingredient of the model, but the predictions for the effective nucleon number are insensitive to it. The uncertainties of nuclear corrections can be largely avoided by considering ratios of quasielastic cross sections between different nuclei.

NUCLEAR REACTIONS ${}_{}{}^{12}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}$, ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}(\pi , {\pi }^{\prime })$, quasielastic scattering; $T_{\pi }=100-400\mathrm{}$ MeV; calculated $\sigma \left(\theta \right)$, semiclassical model; ratios of $\sigma \left(\theta \right)\text{'}\mathrm{s}$.

Levels in ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$ have been excited in the ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}(\alpha , {\alpha }^{\prime }\gamma ){}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$ reaction at $E_{\alpha }=16\mathrm{}$ MeV. Angular correlation and Doppler shift attenuation methods have been used to measure $\gamma$-ray branching ratios, mixing ratios, and lifetimes of bound states up to $E_x=6.9\mathrm{}$ MeV. Values or limits for the transition probabilities for 11 states have been deduced. The data are used to revise the structure of the $K^{\pi }=2^{+} \mathrm{and} 3^{+}$ rotational bands. These bands consist of the following states $E$ (MeV), $J^{\pi }$: for $K^{\pi }=2^{+}, 2.94\left(2^{+}\right), 4.35\left(3^{+}\right), 5.72\left(4^{+}\right)$; for $K^{\pi }=3^{+}, 3.94\left(3^{+}\right), 5.47\left(4^{+}\right)$.

NUCLEAR REACTIONS ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}(\alpha , {\alpha }^{\prime }\gamma )$, $E=16\mathrm{}$ MeV; ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$ measured $E_{\gamma }$, $I_{\gamma }$, $\delta$, $T_{\frac{1}{2}}$; calculated $B\left(\Lambda \right)$; Ge(Li) detector. Enriched target.

We calculate the double differential cross section for inelastic scattering of protons and $\alpha$ particles on ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ and ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$. We use the random-phase-approximation theory of the nucleus, and the distorted-wave Born-approximation theory of the excitation mechanism. In the continum region, excitation energies 10-25 MeV, the experimental cross section exceeds the predicted by a factor of 2-4. We conclude that multistep reactions are important and in some cases dominate at these inelasticities.

NUCLEAR REACTIONS ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}(p, p^{\prime })$, $E=62\mathrm{}$ MeV; ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}(\alpha , {\alpha }^{\prime })$, $E=65\mathrm{}$ MeV; ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}(\alpha , {\alpha }^{\prime })$, $E=99.5\mathrm{}$ MeV; calculated $\sigma (E_p, \theta )$, ($E_{\alpha }, \theta$); DWBA-RPA.

Microscopic DWBA calculations for the ($p, p^{\prime }$) reaction at $E_p=30\mathrm{}$ MeV have been performed for $2^{+}$, $4^{+}$, and $6^{+}$ states in ${}_{}{}^{138}{}_{}{}^{}\mathrm{Ba}$ and ${}_{}{}^{144}{}_{}{}^{}\mathrm{Sm}$. Large-basis shell-model wave functions were used to describe the nuclear states. The effective two-body interaction mediating the inelastic scattering was obtained from a recent survey of inelastic scattering analyses. Polarization charges for the nucleons were extracted using a scheme based on the model of Atkinson and Madsen. Two sets of shell-model wave functions were employed for the ${}_{}{}^{138}{}_{}{}^{}\mathrm{Ba}$ calculation, and it was found that comparison of the inelastic proton scattering calculations with experiment clearly distinguished between the two sets. For the better wave functions, the polarization charges were essentially independent of state and multipole.

NUCLEAR REACTIONS ${}_{}{}^{138}{}_{}{}^{}\mathrm{Ba}(p, p^{\prime })$, ${}_{}{}^{144}{}_{}{}^{}\mathrm{Sm}(p, p^{\prime })$, 30 MeV; calculated $\sigma \left(\theta \right)$; deduced polarization charges.

The ${}_{}{}^{71}{}_{}{}^{}\mathrm{Ga}({}_{}{}^3{}_{}{}^{}\mathrm{He}, d){}_{}{}^{72}{}_{}{}^{}\mathrm{Ge}$ reaction has been studied at 25 MeV incident energy with a split-pole spectrometer. The over-all energy resolution was 18 keV. Sixty ${}_{}{}^{72}{}_{}{}^{}\mathrm{Ge}$ levels, 29 of which observed for the first time, were populated below 5.2 MeV excitation energy. Angular distributions were obtained from 5° to 63° and comparison with distorted-wave-Born-approximation calculations allowed parity assignment and spin limits for 44 levels. Spectroscopic factors are deduced for most of the observed transitions. The whole $2p-1f$ and a weak part of the $3s-2d-1g$ strengths are observed. An interesting result is the strong population of the first excited $0^{+}$ state at 0.690 MeV as compared to the ground state. We present a simple model which can account for this result. Possible $J^{\pi }=0^{+}$ levels in ${}_{}{}^{72}{}_{}{}^{}\mathrm{Ge}$ are found at 2.029 and 3.614 MeV.

NUCLEAR REACTIONS ${}_{}{}^{71}{}_{}{}^{}\mathrm{Ga}({}_{}{}^3{}_{}{}^{}\mathrm{He}, d)$, $E=25\mathrm{}$ MeV; measured $\sigma \left(\theta \right)$; ${}_{}{}^{72}{}_{}{}^{}\mathrm{Ge}$ deduced levels up to 5.2 MeV, $J$, $\pi$, $S$.

Data for $\gamma$ transitions extracted from particle-$\gamma$ angular correlation functions, which are measured as a function of the particle angle, are shown to be of similar quality as the data extracted by methods in which the $\gamma$ angle is varied. The data extracted in this way are believed to complete usefully the data obtained by the conventional methods. As an example the reaction ${}_{}{}^{52}{}_{}{}^{}\mathrm{Cr}(d, p\gamma ){}_{}{}^{53}{}_{}{}^{}\mathrm{Cr}$ is studied. The correlation functions are calculated with the distorted wave Born approximation. The extracted mixing ratios are found to be nearly independent of the parameters of the optical potential.

NUCLEAR REACTIONS ${}_{}{}^{52}{}_{}{}^{}\mathrm{Cr}(d, p\gamma )$, $E=10\mathrm{}$ MeV; measured $\sigma (E_p, \theta )$, Angular correlation functions $W({\theta }_p, {\theta }_{\gamma }=90\mathrm{}°)$; DWBA analyses; deduced mixing ratios, dependence on potential parameters; enriched targets.

A beam of 11.4-MeV photons, extracted from the CP-5 reactor, has been used in a high resolution measurement of the differential cross section for photon scattering by nuclei ranging from ${}_{}{}^{141}{}_{}{}^{}\mathrm{Pr}$ to ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$. Inelastic scattering which leaves the residual nucleus in a state of the ground state rotational band, i.e., nuclear Raman scattering, was measured relative to elastic scattering. The data confirm the trends observed earlier in measurements at 10.83 MeV. The strength of inelastic scattering has been compared with the predictions of simple models of the giant dipole resonance. The implication of deviations of measured cross sections from predictions of the simple rotator model are discussed. These discrepancies are significant in the lanthanide region and may be viewed as evidence for the existence of a small direct nonresonant reaction component in the region of the giant dipole resonance.

NUCLEAR REACTIONS ${}_{}{}^{141}{}_{}{}^{}\mathrm{Pr}$, ${}_{}{}^{159}{}_{}{}^{}\mathrm{Tb}$, ${}_{}{}^{165}{}_{}{}^{}\mathrm{Ho}$, ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$, ${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}$, ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}(\gamma , {\gamma }^{\prime })$, $E_{\gamma }=11.387\mathrm{}$ MeV; measured $\sigma \left(\theta \right)$, elastic scattering, inelastic scattering to g.s. rotational band. Ge(Li) detector, 10 keV at 10 MeV.

A clean separation of compound nucleus from noncompound nucleus processes in ($\alpha , {\alpha }^{\prime }$) reactions is made for 18-MeV $\alpha$-particles on Ni, Zn, and Sn. Experimental results agree well with both Weisskopf and Hauser-Feshbach theory using Gilbert-Cameron level densities. In addition, a surprising theoretical prediction in the case of Ni is dramatically confirmed by experiment.

NUCLEAR REACTIONS ${}_{}{}^{58,60,62}{}_{}{}^{}\mathrm{Ni}(\alpha , {\alpha }^{\prime })$, ${}_{}{}^{64,66}{}_{}{}^{}\mathrm{Zn}(\alpha , {\alpha }^{\prime })$, ${}_{}{}^{112}{}_{}{}^{}\mathrm{Sn}(\alpha , {\alpha }^{\prime })$, $E=18\mathrm{}$ MeV; measured $\frac{d^2\sigma }{d\Omega \mathrm{dE}}$, deduced compound-nucleus contribution to cross section, compared with calculations from Weisskopf, Hauser-Feshbach statistical theory.

Mass distributions for thermal-neutron-induced fission ($n, f$) of ${}_{}{}^{255}{}_{}{}^{}\mathrm{Fm}$ and ${}_{}{}^{251}{}_{}{}^{}\mathrm{Cf}$ have been determined radiochemically. Both mass distributions are asymmetric with a peak-to-valley ratio of about 2.6 for ${}_{}{}^{255}{}_{}{}^{}\mathrm{Fm}$ and about 13 for ${}_{}{}^{251}{}_{}{}^{}\mathrm{Cf}$. Cross sections were determined to be 3200±320 b for ${}_{}{}^{255}{}_{}{}^{}\mathrm{Fm}(n, f)$ and 5300±530 b for ${}_{}{}^{251}{}_{}{}^{}\mathrm{Cf}(n, f)$.

NUCLEAR REACTIONS, FISSION ${}_{}{}^{255}{}_{}{}^{}\mathrm{Fm}(n, f)$, ${}_{}{}^{251}{}_{}{}^{}\mathrm{Cf}(n, f)$, $E=0.025\mathrm{}$ eV; measured radiochemical mass yields and ${\sigma }_f$.

Energy levels in ${}_{}{}^{62}{}_{}{}^{}\mathrm{Ni}$ up to an excitation energy of 6.4 MeV have been studied by the ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}(p, t){}_{}{}^{62}{}_{}{}^{}\mathrm{Ni}$ reaction at 40 MeV bombarding energy with an over-all resolution of 12 keV full width at half maximum. Spins and parities are assigned to levels which were excited with characteristic angular distributions. These include $0^{+}$ states at 2.05, 2.89, 4.23, 4.62, and 5.45 MeV. A distorted-wave analysis based on shell-model wave functions was performed and compared to the experimental differential cross sections.

NUCLEAR REACTIONS ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}(p, t)$, $E=40\mathrm{}$ MeV; measured $\sigma (E_t, \theta )$; enriched target. ${}_{}{}^{62}{}_{}{}^{}\mathrm{Ni}$ deduced levels, $L$, $J$, $\pi$.

The reaction ${}_{}{}^{89}{}_{}{}^{}\mathrm{Y}(t, p){}_{}{}^{91}{}_{}{}^{}\mathrm{Y}$ has been measured at an incident energy of 20 MeV. Differential cross sections were measured at 13 angles and an excitation range of 5 MeV was observed with 18 keV resolution. The data are compared to distorted wave calculations both for $L$ assignments and magnitude relations. Sixteen new levels are reported in ${}_{}{}^{91}{}_{}{}^{}\mathrm{Y}$ as well as many new limits on spin assignments. An interpretation of the results as a proton hole coupled to ${}_{}{}^{92}{}_{}{}^{}\mathrm{Zr}$ pairing-multipole states is presented. Such an analysis provides a qualitative description of the observed strength, but a more complex analysis is required for quantitative results.

NUCLEAR REACTIONS ${}_{}{}^{89}{}_{}{}^{}\mathrm{Y}(t, p){}_{}{}^{91}{}_{}{}^{}\mathrm{Y}$, $E_t=20\mathrm{}$ MeV; measured $\sigma (E_p, \theta )$; ${}_{}{}^{91}{}_{}{}^{}\mathrm{Y}$ deduced levels, $L$, $\pi$; DWBA analysis.

Excitation functions for complete fusion have been measured for ${}_{}{}^{35}{}_{}{}^{}\mathrm{Cl}$ projectiles on ${}_{}{}^{58,60,62,64}{}_{}{}^{}\mathrm{Ni}$. Deviations from the predictions of the sharp cutoff model are observed and compared with calculations based on the formalism of Wong. In this picture tunneling and static deformation of target and projectile can explain the experimental data in the barrier region.

NUCLEAR REACTIONS complete fusion, ${}_{}{}^{58,60,62,64}{}_{}{}^{}\mathrm{Ni}$ + ${}_{}{}^{35}{}_{}{}^{}\mathrm{Cl}$, $E_{\mathrm{lab}}=91-170\mathrm{}$ MeV; measured $\sigma (\theta , E)$ for evaporation residues.

Measurements of the electron-photon double decay of the 514-keV state in ${}_{}{}^{85}{}_{}{}^{}\mathrm{Rb}$ have been performed at a relative angle of emission of 30° using a fast-slow double coincidence system with a three-dimensional analyzer. The energy spectra of photons and double-decay differential coefficients for $K\gamma$ decay and $\mathrm{}(L+M+N)\mathrm{}\gamma$ decay have been derived from the counting rates. The results are in agreement with the theory of the internal Compton effect of Spruch and Goertzel.

RADIOACTIVITY ${}_{}{}^{85}{}_{}{}^{}\mathrm{Rb}_{}^m{}_{}{}^{}$; measured $e\gamma$ double decay at 30°; deduced photon energy distribution in the range 20 to 132 keV for $K\gamma$ decay and 28 to 132 keV for $\mathrm{}(L+M+N)\mathrm{}\gamma$ decay.

The level scheme of ${}_{}{}^{173}{}_{}{}^{}\mathrm{Lu}$ as populated by the decay of 23.9-h ${}_{}{}^{173}{}_{}{}^{}\mathrm{Hf}$ has been studied using Ge(Li) detectors in singles and coincidence $\gamma$-ray spectrometers. The coincidence data provide strong support for nearly all the previously proposed levels. Singles data obtained with a Compton-suppression spectrometer have enabled us to identify very weak transitions which were not seen by previous experimenters. Some of these transitions are used to establish new levels at 721.56, 734.63, 1359.32, and 1408.90 keV and arguments are presented for assignment of these levels as the ½[660], $\frac{7}{2}\mathrm{}\left[523\right]\mathrm{}$, ($\frac{3}{2}\mathrm{}\left[402\right]+\frac{3}{2}\mathrm{}\left[651\right]\mathrm{}$), and ½[400] Nilsson states.

RADIOACTIVITY ${}_{}{}^{173}{}_{}{}^{}\mathrm{Hf}$ [from ${}_{}{}^{172}{}_{}{}^{}\mathrm{Yb}(\alpha , 3n)$, ${}_{}{}^{173}{}_{}{}^{}\mathrm{Yb}(\alpha , 2n)$]; measured $E_{\gamma }$, $I_{\gamma }$, $\gamma \gamma$-coin, $T_{\frac{1}{2}}$; deduced $log\mathrm{ft}$. ${}_{}{}^{173}{}_{}{}^{}\mathrm{Lu}$ deduced levels, $J$, $\pi$. Ge(Li) detectors, enriched targets.