Angular distributions have been measured for transitions populating residual states of ${}_{}{}^{163}{}_{}{}^{}\mathrm{Dy}$ and ${}_{}{}^{165}{}_{}{}^{}\mathrm{Er}$ through the ($d,t$) reaction at $E_d=17\mathrm{}$ MeV. Many of these angular distributions have shapes which are well reproduced by distorted wave Born approximation calculations which assume orbital angular momentum transfers $l$ which are compatible with the previously assigned spin-parities of the states. But a significant number of angular distributions are anomalous; i.e., either they cannot be fitted by any reasonable distorted wave Born approximation calculation or they can only be fitted with a calculation which assumes an $l$ value incompatible with the previous Nilsson model assignment of the state. While the summed spectroscopic factors are in good agreement with Nilsson model expectations, there is considerable evidence of fragmentation of single-quasihole strength (most dramatically for ${}_{}{}^{164}{}_{}{}^{}\mathrm{Dy}$→${}_{}{}^{163}{}_{}{}^{}\mathrm{Dy}$ $l=0\mathrm{}$ transitions, 12 of which are observed) and the spectroscopic factors for several levels deviate significantly from Nilsson model predictions, even though Coriolis coupling has been included in the model calculation. This observation of several strongly anomalous angular distributions, along with large discrepancies between observed and model-predicted spectroscopic factors, almost certainly indicates that the assumption of a simple one-step direct reaction mechanism breaks down for some of these transitions. No evidence is found to indicate the position of the (expected strongly populated) ${7/2}^{+}$[404] state. Several other possible changes in previous Nilsson model assignments are indicated.

NUCLEAR REACTIONS ${}_{}{}^{164}{}_{}{}^{}\mathrm{Dy}(d,t)$, ${}_{}{}^{166}{}_{}{}^{}\mathrm{Er}(d,t)$, $E_d=17\mathrm{}$ MeV measured $\sigma \left(\theta \right)$; DWBA analysis, deduced levels, $l$ values, spectroscopic factors. Enriched targets.

$J^{\pi }={\frac{3}{2}}^{-}$ levels to which $L=0\mathrm{}$ ($p,t$) transitions are observed have been identified in ${}_{}{}^{73}{}_{}{}^{}\mathrm{As}$ at 0 (100%), 396 (2.4%), 656 (3%), and 1595 (1.5%) keV. The shapes of the angular distributions for the ground state and 656 keV level are identical to those corresponding to the two $0^{+}$ levels of ${}_{}{}^{72}{}_{}{}^{}\mathrm{Ge}$ at 0 (100%) and 690 (27%) keV. Some of these results, the large difference in relative intensities of the pure $L=0\mathrm{}$ transitions to the levels at 690 keV in ${}_{}{}^{72}{}_{}{}^{}\mathrm{Ge}$ (27%) and 656 keV in ${}_{}{}^{73}{}_{}{}^{}\mathrm{As}$ (3%) and the fact that two other $L=0\mathrm{}$ transitions are observed in ${}_{}{}^{73}{}_{}{}^{}\mathrm{As}$, significantly differ from those expected for strict weak coupling core excitation. It is shown that weak coupling is indeed a poor approximation for the two $0^{+}$ levels of ${}_{}{}^{72}{}_{}{}^{}\mathrm{Ge}$, due to the "blocking" of the proton $p_{\frac{3}{2}}$ orbital.

NUCLEAR REACTIONS ${}_{}{}^{74}{}_{}{}^{}\mathrm{Ge}\mathrm{}(p,t)\mathrm{}$, ${}_{}{}^{75}{}_{}{}^{}\mathrm{As}\mathrm{}(p,t)\mathrm{}$, $E=26\mathrm{}$ MeV, measured $\sigma \left(\theta \right)$; ${}_{}{}^{73}{}_{}{}^{}\mathrm{As}$ deduced levels, $J$, $\pi$.

NUCLEAR STRUCTURE ${}_{}{}^{73}{}_{}{}^{}\mathrm{As}$; weak coupling core-excitation model.

Excitation functions for 12 nuclear reactions of type ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}\mathrm{}\left[\right(p,(2-4\mathrm{})p,\mathrm{}(1-6)n]$ have been measured for incident proton energies from 10-86 MeV. The complex excitation functions have been decomposed to yield a component due to emission of one or two $\alpha$ particles, and a component due to the emission of individual nucleons. Combining the $\alpha$ particle portions of the decomposed excitation functions, the excitation energy spectra for those events associated with $\alpha$ particle emission have been derived. Having estimated the excitation functions for a few missing reactions, the total probability of emission of seven combinations of charged particles as a function of incident proton energy has been calculated. The implications of the results on the preequilibrium model of nuclear reactions are discussed.

NUCLEAR REACTIONS ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}(p,ypxn)$, $y=2-4\mathrm{}$, $x=1-6\mathrm{}$, $E=10-86\mathrm{}$ MeV; measured $\sigma \mathrm{}\left(E\right)\mathrm{}$; deduced $\alpha$; particle yields, charged-particle emission probabilities. Enriched target.

Thermal neutron capture in enriched and natural neodymium targets and average-resonance neutron capture in natural-neodymium targets yield high- and medium-energy $\gamma$-ray spectra. These spectra are compared with each other to determine the energies and relative intensities of $\gamma$ rays from ${}_{}{}^{146}{}_{}{}^{}\mathrm{Nd}$ which are then used to construct a partial level scheme for ${}_{}{}^{146}{}_{}{}^{}\mathrm{Nd}$. A cooled intrinsic-germanium detector is used in both coincidence and anticoincidence modes of operation to measure the spectra. Of 146 $\gamma$ rays observed in the 400 to 2800 keV range, 56 are located as transitions among 33 states. Thirty-one primary transitions following average neutron capture are used to describe all but one of the excited states. Most of the states are newly reported here with definite parity assignments and restricted spin choices. A search for the $2^{+}$ member of a previously suggested two-phonon triplet indicates that the existence of this member is not likely. The capture state energy is determined to be 7564.7 ± 0.4 keV.

NUCLEAR REACTIONS ${}_{}{}^{145}{}_{}{}^{}\mathrm{Nd}(n,\gamma )$, $E_n=\mathrm{thermal}$, measured $E_{\gamma }$, $I_{\gamma }$, 0.45-2.85 MeV, 4.5-7.1 MeV, intrinsic germanium detector (IGD), thermal neutrons; measured $E_{\gamma }$, $I_{\gamma }$, 4.5-7.1 MeV, average resonance reutrons IGD; level scheme for ${}_{}{}^{146}{}_{}{}^{}\mathrm{Nd}$, $J^{\pi }$, $\gamma$-ray branching.

The six polarization transfer coefficients $K_z^{x^{\prime }}$, $K_z^{z^{\prime }}$, $K_x^{z^{\prime }}$, $K_x^{x^{\prime }}$, $K_y^{y^{\prime }}$, and $K_{yy}^{y^{\prime }}$ for the reaction ${}_{}{}^3{}_{}{}^{}\mathrm{H}\mathrm{}(d,n)\mathrm{}{}_{}{}^4{}_{}{}^{}\mathrm{He}$ have been measured at a laboratory deuteron energy of 7.0 MeV. The laboratory angular range 0° to 105° was covered. Special attention is given to the zero degree longitudinal polarization transfer case, where it is shown that a beam of neutrons with accurately known polarization may be produced.

NUCLEAR REACTIONS ${}_{}{}^3{}_{}{}^{}\mathrm{H}\mathrm{}(d,n)\mathrm{}$, $E=7.0\mathrm{}$ MeV, measured analyzing powers $A_y$, $A_{xx}$, $A_{yy}$, $A_{zz}$, polarization function $P^{y^{\prime }}$; and polarization transfer coefficients $K_z^{x^{\prime }}$, $K_z^{z^{\prime }}$, $K_x^{z^{\prime }}$, $K_x^{x^{\prime }}$, $K_y^{y^{\prime }}$, and $K_{yy}^{y^{\prime }}$ at ${\theta }_{\mathrm{lab}}=0\mathrm{}°$ to ${\theta }_{\mathrm{lab}}=105\mathrm{}°$. Enriched target.

The ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}\mathrm{}(d,n)\mathrm{}$ reaction has been studied at 6.0, 8.0, and 10.0 MeV deuteron bombarding energies. The neutron spectrum was determined with the time-of-flight method and the overall time resolution was about 2 ns. Targets with natural and enriched abundances of ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$ were used. Angular distributions of neutrons leading to states in ${}_{}{}^{57}{}_{}{}^{}\mathrm{Co}$ were measured between 20° and 100°. The measured cross sections were analyzed in the framework of the distortedwave Born approximation theory to deduce $l_p$ values and proton transition strengths. For the lowest bombarding energy the compound-nucleus mechanism was also taken into account. The experimental results were compared with the corresponding data from (${}_{}{}^3{}_{}{}^{}\mathrm{He},d$) reactions and other ($d,n$) studies and with existing theoretical calculations of proton strengths in ${}_{}{}^{57}{}_{}{}^{}\mathrm{Co}$.

NUCLEAR REACTIONS ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}\mathrm{}(d,n)\mathrm{}$, $E_d=6.0, 8.0, \mathrm{and} 10.0$ MeV; measured $\sigma (E_n,\theta )$. ${}_{}{}^{57}{}_{}{}^{}\mathrm{Co}$ deduced $l$, $j$, $\pi$, and $S$. Natural and enriched targets.

Two features of the ($d,p$) stripping reaction to the continuum, the parallelism between the excitation functions of energy-differential stripping cross section $\frac{d^2\sigma }{d\Omega \mathrm{dE}}$ and the total neutron-target elastic scattering cross section ${\sigma }_{\mathrm{tot}}(n,n)$, and the dependence of the ratio $\frac{\left(\frac{d^2\sigma }{d\Omega \mathrm{dE}}\right)}{{\sigma }_{\mathrm{tot}}(n,n)}$ on transferred angular momentum ($l$), are explained satisfactorily by a plane wave Butler approximation for a ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$ target nucleus. It appears that the $l$ dependence of the above ratio is so dominant that even the crude Butler approximation suffices for identification of $l$ values. The ($d,p$) and ($d,n$) angular distributions are also calculated for the targets ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$, and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, leading to unbound states by this method. The results are compared with experiment and with these obtained by distorted wave Born approximation method employing an extrapolation technique to treat the neutron wave in the continuum.

NUCLEAR REACTIONS Calculated $\frac{\left(\frac{d^2\sigma }{d\Omega \mathrm{dE}}\right)}{{\sigma }_{\mathrm{tot}}(n,n)}$, $\frac{d\sigma \mathrm{}(d,p)\mathrm{}}{d\Omega }$, $\frac{d\sigma \mathrm{}(d,n)\mathrm{}}{d\Omega }$; unbound states; $E_D=6-15\mathrm{}$ MeV.

The ($p,2p$) reaction on the target nuclei ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ has been studied at 100 MeV bombarding energy. The energies of both the outgoing protons have been measured in coincidence in a coplanar symmetric geometry with good energy and momentum resolution in order to separate the different excited states of the residual nuclei. The experimental data are presented in a form suitable for direct comparison with direct knockout theory (impulse approximation). The distorted wave impulse approximation model can explain the qualitative features of the energy sharing and angular correlation spectra. The detailed quantitative agreement with the distorted wave impulse approximation is, however, somewhat poor, indicating the necessity for a more exact treatment of the three-body reaction mechanism.

NUCLEAR REACTIONS ${}_{}{}^7{}_{}{}^{}\mathrm{Li}\mathrm{}(p,2p)\mathrm{}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}\mathrm{}(p,2p)\mathrm{}$, $E_p=100\mathrm{}$ MeV; measured $\sigma (E,{\theta }_1,{\theta }_2)$; deduced distorted recoil momentum distributions; separation energy resolution 0.8 MeV; DWIA analysis.

The excitation function for the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$) reaction has been measured up to incident energies of 31 MeV, and the ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ recoil properties determined in a series of catcher foil experiments at 30 MeV. Based on the different recoil properties of ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ formed by each of four different mechanisms, the contribution of each has been estimated. At 30 MeV the predominant mode of ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ formation is through sequential decay of the compound nucleus ${\left[{}_{}{}^{15}{}_{}{}^{}\mathrm{O}\right]}^{*}\to {\left[{}_{}{}^{11}{}_{}{}^{}\mathrm{C}\right]}^{*}+{\alpha }_1\to {}_{}{}^7{}_{}{}^{}\mathrm{Be}+{\alpha }_2+{\alpha }_1$ (≅39 mb). This is followed in importance by the direct $n$ pickup reaction to certain excited states in ${}_{}{}^{11}{}_{}{}^{}\mathrm{C}$ followed by $\alpha$-particle emission ${\left[{}_{}{}^{11}{}_{}{}^{}\mathrm{C}\right]}^{*}\to {}_{}{}^7{}_{}{}^{}\mathrm{Be}+\alpha$. The direct $\alpha$ particle pickup reaction and compound nucleus evaporation of ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ have smaller cross sections (≅1 mb and ≫1 mb, respectively).

NUCLEAR REACTIONS ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$), $E\le 31$ MeV; measured $\sigma (E,\theta )$; deduced reaction mechanisms.

The ${}_{}{}^6{}_{}{}^{}\mathrm{Li}(t,{}_{}{}^3{}_{}{}^{}\mathrm{He}){}_{}{}^6{}_{}{}^{}\mathrm{He}\mathrm{}\left(0.0\right)\mathrm{}$ and ${}_{}{}^6{}_{}{}^{}\mathrm{Li}(t,t^{\prime }){}_{}{}^6{}_{}{}^{}\mathrm{Li}\mathrm{}\left(3.56\right)\mathrm{}$ transitions have been studied at 17 MeV triton incident energy. Differential cross sections have been obtained from 10° to 90° c.m. angle, with 12 angles common to both reactions. The experimental ratio of $\sigma (t,{}_{}{}^3{}_{}{}^{}\mathrm{He})$ to $\sigma (t,t^{\prime })$ is 2.28 ± 0.16 while geometrical isospin considerations for this reaction pair would predict a ratio of 2.0. Corrections based on a microscopic distorted-wave Born-approximation calculation of charge exchange and inelastic scattering do not account for a deviation of this magnitude.

NUCLEAR REACTIONS ${}_{}{}^6{}_{}{}^{}\mathrm{Li}(t,{}_{}{}^3{}_{}{}^{}\mathrm{He}){}_{}{}^6{}_{}{}^{}\mathrm{He}\mathrm{}\left(0.0\right)\mathrm{}$, ${}_{}{}^6{}_{}{}^{}\mathrm{Li}(t,t^{\prime }){}_{}{}^6{}_{}{}^{}\mathrm{Li}\mathrm{}\left(3.56\right)\mathrm{} E_t=17.0\mathrm{}$ MeV; measured $\sigma \left(\theta \right)$; DWBA analysis.

We have experimentally located a polarization extremum ($A_y=-1\mathrm{}$) in triton-α elastic scattering near $E_t=11.1\mathrm{}$ MeV, ${\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}=95\mathrm{}°$. This is the first application and test of a Lamb-shift polarized tritium ion source which has been installed on the Los Alamos tandem accelerator. The results verify the accuracy of the quench-ratio method for the determination of the polarization of the triton beam.

NUCLEAR REACTIONS ${}_{}{}^4{}_{}{}^{}\mathrm{He}(\overrightarrow{t},t)$; $E_t=10.2\mathrm{}-11.7$ MeV, measured $A_y\left(\theta \right)$. Demonstrated existence of $A_y=-1\mathrm{}$ point.

Nonlocality is characteristic of potentials describing processes in which degrees of freedom are eliminated, and provides for a description of a much wider variety of phenomena than that encountered with short range local potentials. In this paper, properties of the radial equation for symmetric nonlocal potentials are investigated, using a configuration space approach and restricting the analysis to real $k$. Emphasis is placed on identifying those constraints associated with a local potential which are relaxed in going from a local to a nonlocal potential. The Fredholm determinants associated with the integral equations for the physical, regular, and Jost solutions are central to the development. Unlike the case for a short range local potential, for a nonlocal potential these Fredholm determinants can vanish for real $k\ne 0$. It is shown that when $D^{\pm }\mathrm{}\left(k\right)=0\mathrm{}$ the other Fredholm determinants are zero as well. The properties of the solutions at the zeroes of the Fredholm determinants are discussed in this context, and the concepts "spurious state" and "continuum bound state" are clarified. The behavior of solutions is illustrated with examples.

NUCLEAR REACTIONS Scattering by a nonlocal potential, Fredholm determinants and their zeroes, continuum bound states, spurious states.

$\alpha$-particle yields from the ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}(n,\alpha ){}_{}{}^7{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Li}_{}^{*}{}_{}{}^{}$ reactions have been measured at eight angles between 0° and 150° for neutron energies between 200 and 1250 keV. A thick natural lithium target bombarded by a polsed proton beam provided a neutron-energy continuum. $\alpha$ particles from the two reactions were distinguished by measuring the sum of $\alpha$-particle and neutron flight times as well as $\alpha$-particle energies. Yield data were converted to c.m. differential cross sections and each angular distribution was fitted with a series of Legendre polynomials. Coefficients of the $P_0$ terms are compared with other measurements. The coefficients of the higher order terms are qualitatively interpreted in terms of the level structure of ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$.

NUCLEAR REACTIONS ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}(n,{\alpha }_0)$, ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}(n,{\alpha }_1)$; $E=0.2\mathrm{}-1.25$ MeV, measured $\sigma \left(\theta \right)$.

Differential cross sections of elastic scattering of 104 MeV $\alpha$ particles from ${}_{}{}^{204,206,208}{}_{}{}^{}\mathrm{Pb}$ have been measured with high angular accuracy. The analyses are based on a folding model treating the proton and neutron distributions independently. The proton distributions were taken from precise electron scattering results. The neutron distributions were parametrized by a modified Gaussian the parameters of which were varied in order to fit the experimental cross sections. The resulting rms radii of the neutron distributions exceed the rms radii of the proton distributions by $\Delta r=0.22\mathrm{}\pm 0.09$ fm for ${}_{}{}^{204}{}_{}{}^{}\mathrm{Pb}$, $\Delta r=0.19\mathrm{}\pm 0.09$ fm for ${}_{}{}^{206}{}_{}{}^{}\mathrm{Pb}$, and $\Delta r=0.30\mathrm{}\pm 0.07$ fm for ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$.

NUCLEAR REACTIONS ${}_{}{}^{204,206,208}{}_{}{}^{}\mathrm{Pb}(\alpha ,\alpha )$, $E_{\alpha }=104\mathrm{}$ MeV; measured $\sigma \left(\theta \right)$, $\theta =10\mathrm{}-48°$, enriched targets; microscopic optical model analysis; deduced neutron density rms radii.

The level structure and the decay properties of levels in ${}_{}{}^{93}{}_{}{}^{}\mathrm{Mo}$ have been investigated via ${}_{}{}^{93}{}_{}{}^{}\mathrm{Nb}\mathrm{}(p,n)\mathrm{}{}_{}{}^{93}{}_{}{}^{}\mathrm{Mo}_{}^{*}{}_{}{}^{}\left(\gamma \right)$ reaction spectrometry at 3.7 and 4.4 MeV. A detailed decay scheme that includes many new levels in ${}_{}{}^{93}{}_{}{}^{}\mathrm{Mo}$ up to 3.07 MeV of excitation has been constructed from measurements of $\gamma$-ray energies and relative intensities from anti-compton spectra and from $\gamma -\gamma$ coincidence measurements. Values or limits for the lifetimes of 40 levels in ${}_{}{}^{93}{}_{}{}^{}\mathrm{Mo}$ were obtained from Doppler-shift attenuation measurements using the centroid shift technique. $J^{\pi }$ assignments and multipole mixing ratios were deduced from angular distribution measurements of singles $\gamma$-ray spectra recorded with the anti-Compton spectrometer. Values or limits for $B\left(\Lambda \right)$ were extracted for many transitions in ${}_{}{}^{93}{}_{}{}^{}\mathrm{Mo}$. The experimental results are compared with calculations based on the intermediate coupling model and the shell model. The transition rates are found to be in reasonable agreement with the intermediate coupling model. This model, however, unlike the shell model, does not predict the existence of observed low-lying high-spin states with $J\ge \frac{13}{2}$.

NUCLEAR REACTIONS ${}_{}{}^{93}{}_{}{}^{}\mathrm{Nb}\mathrm{}(p,n)\mathrm{}{}_{}{}^{93}{}_{}{}^{}\mathrm{Mo}_{}^{*}{}_{}{}^{}\left(\gamma \right)$, $E=3.7, 4.4$ MeV, monoisotopic target. Measured $E_{\gamma }$, $I_{\gamma }$, $E_{\gamma }\left(\theta \right)$, $\Delta E_{\gamma } \left(\tau \right)$, $\gamma -\gamma$ coinc., deduced ${}_{}{}^{93}{}_{}{}^{}\mathrm{Mo}$ levels, $J$, $\pi$, branching fractions, $\tau$, $\delta \left(\frac{E2\mathrm{}}{M1\mathrm{}}\right)$, $B\mathrm{}\left(E2\mathrm{}\right)\mathrm{}$, $B\mathrm{}\left(M1\mathrm{}\right)\mathrm{}$, and $B\mathrm{}\left(E1\mathrm{}\right)\mathrm{}$ values; Ge(Li) detectors, Ge(Li)-NaI(T1) anti-Compton spectrometer, 1.9 keV.

The nucleus ${}_{}{}^{70}{}_{}{}^{}\mathrm{Ge}$ has been studied via the ${}_{}{}^{68}{}_{}{}^{}\mathrm{Zn}(\alpha ,2n\gamma ){}_{}{}^{70}{}_{}{}^{}\mathrm{Ge}$ reaction at $E_{\alpha }\simeq 30$ MeV using different in-beam $\gamma$ spectroscopic techniques. Levels up to 5.5 MeV have been identified and spins up to $8^{+}$ have been established.

NUCLEAR REACTIONS ${}_{}{}^{68}{}_{}{}^{}\mathrm{Zn}(\alpha ,2n\gamma )$ $E_{\alpha }\simeq 30$ MeV, $\gamma \gamma$ coincidences, angular distributions, level scheme deduced.

An improved expression for the nuclear level density is obtained by introducing a higher term in the expansion of the excitation energy in terms of nuclear temperature. The new term leads to better fitting with the experimental results especially at the high excitation energy part of the spectrum. The level density parameters were calculated for the nuclei ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ti}$, ${}_{}{}^{53}{}_{}{}^{}\mathrm{Mn}$, ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{58}{}_{}{}^{}\mathrm{Co}$, ${}_{}{}^{65}{}_{}{}^{}\mathrm{Zn}$, ${}_{}{}^{113}{}_{}{}^{}\mathrm{Sn}$, and ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sb}$. For the two last nuclei the spin dependent level density was considered.

NUCLEAR REACTIONS New expressions calculated for level density parameters derived for ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ti}$, ${}_{}{}^{53}{}_{}{}^{}\mathrm{Mn}$, ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{58}{}_{}{}^{}\mathrm{Co}$, ${}_{}{}^{65}{}_{}{}^{}\mathrm{Zn}$, ${}_{}{}^{113}{}_{}{}^{}\mathrm{Sn}$, ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sb}$.

The level structures of the shape transitional nuclei ${}_{}{}^{190}{}_{}{}^{}\mathrm{Pt}$ and ${}_{}{}^{192}{}_{}{}^{}\mathrm{Pt}$ have been studied by ($\alpha ,xn\gamma$) reactions on enriched Os targets. The measurements included $\gamma$-ray singles, prompt and delayed $\gamma -\gamma$ conincidences, half-life determinations in the range 1-500 ns, and $\gamma$-ray angular distributions. Detailed level schemes for ${}_{}{}^{190}{}_{}{}^{}\mathrm{Pt}$ and ${}_{}{}^{192}{}_{}{}^{}\mathrm{Pt}$, incorporating much new spectroscopic information, are reported. Acute backbending observed at about spin 10 in the positive parity yrast sequences of the two nuclei is attributed to intersection of the ground bands by rotation aligned bands of both ($\nu i_{\frac{13}{2}}^{}{}_{}{}^{-2\mathrm{}}$) and ($\pi h_{\frac{11}{2}}^{}{}_{}{}^{-2\mathrm{}}$) character. A description of well-developed $5^{-}$ bands observed in both nuclei as semidecoupled ($\nu i_{\frac{13}{2}}, \nu$) bands is briefly discussed. ${10}^{-}$ isomers with half-lives of 47±6 ns in ${}_{}{}^{190}{}_{}{}^{}\mathrm{Pt}$ and 250±30 ns in ${}_{}{}^{192}{}_{}{}^{}\mathrm{Pt}$ are reported. The nature of these isomers is discussed in light of our related finding that the neighboring nuclei ${}_{}{}^{189,191,193}{}_{}{}^{}\mathrm{Pt}$ have triaxial shapes ($\gamma \sim 30°$), and it is concluded that the ${10}^{-}$ states are predominantly of ($\nu i_{\frac{13}{2}}, \nu h_{\frac{9}{2}}$) two-quasiparticle composition.

NUCLEAR REACTIONS ${}_{}{}^{190,192}{}_{}{}^{}\mathrm{Os}(\alpha ,4n\gamma )$, ${}_{}{}^{188,190}{}_{}{}^{}\mathrm{Os}(\alpha ,2n\gamma )$, $E=28\mathrm{}-50$ MeV; measured $E_{\gamma }$, $I_{\gamma }\left(\theta \right)$, $\gamma -\gamma$ coin, $\gamma -t$ relationships; ${}_{}{}^{190,192}{}_{}{}^{}\mathrm{Pt}$ deduced level schemes, $J$, $\pi$, $T_{\frac{1}{2}}$.

${\frac{13}{2}}^{+}$ isomers with half-lives of 311 ± 15, 143 ± 5, and 95 ± 5 μs in ${}_{}{}^{187}{}_{}{}^{}\mathrm{Pt}$, ${}_{}{}^{189}{}_{}{}^{}\mathrm{Pt}$, and ${}_{}{}^{191}{}_{}{}^{}\mathrm{Pt}$, respectively, have been observed in ($\alpha ,3n\gamma$) reactions on isotopically enriched Os targets. Isomeric decay schemes based on the present measurements and on ${}_{}{}^{189}{}_{}{}^{}\mathrm{Au}$ and ${}_{}{}^{191}{}_{}{}^{}\mathrm{Au}$ decay data are presented. It is proposed that the ${}_{}{}^{187,189,191}{}_{}{}^{}\mathrm{Pt}{\frac{13}{2}}^{+}$ isomers deexcite by $M2\mathrm{}$ transitions to ${\frac{9}{2}}^{-}$ intrinsic states of $\nu h_{\frac{9}{2}}$ character. In $A\ge 193$ Pt nuclei the corresponding ${\frac{9}{2}}^{-}$ states must lie above the known $\nu i_{\frac{13}{2}}$ isomers, which have much longer half-lives.

NUCLEAR REACTIONS ${}_{}{}^{186,188,190,192}{}_{}{}^{}\mathrm{Os}(\alpha ,3n\gamma )$, $E=30\mathrm{}-50$ MeV, enriched targets; measured $\sigma \mathrm{}\left(E\right)\mathrm{}$, $E_{\gamma }$, $I_{\gamma }$, $\gamma -\gamma$ coin, $\sigma \left(\theta \right)\gamma$, $T_{\frac{1}{2}}$, deduced ${}_{}{}^{187}{}_{}{}^{}\mathrm{Pt}$, ${}_{}{}^{189}{}_{}{}^{}\mathrm{Pt}$, ${}_{}{}^{191}{}_{}{}^{}\mathrm{Pt}$ isomeric decay schemes, $J$, $\pi$.

We have investigated the proton transfer reactions ${}_{}{}^{86}{}_{}{}^{}\mathrm{Sr}\mathrm{}(d,n)\mathrm{}{}_{}{}^{87}{}_{}{}^{}\mathrm{Y}$, ${}_{}{}^{87}{}_{}{}^{}\mathrm{Sr}\mathrm{}(d,n)\mathrm{}{}_{}{}^{88}{}_{}{}^{}\mathrm{Y}$, and ${}_{}{}^{88}{}_{}{}^{}\mathrm{Sr}\mathrm{}(d,n)\mathrm{}{}_{}{}^{89}{}_{}{}^{}\mathrm{Y}$ at 12 MeV incident deuteron energy. Spectroscopic factors are extracted from a distorted wave Born approximation analysis and compared to the spectroscopic factors extracted from the analogous (${}_{}{}^3{}_{}{}^{}\mathrm{He},d$) reactions. A comparison is also made of the ($d,n$) and ($d,{}_{}{}^3{}_{}{}^{}\mathrm{He}$) reactions to determine fractional emptiness and occupation probability of shell model orbitals. Additionally, ground state proton configurations of ${}_{}{}^{86}{}_{}{}^{}\mathrm{Sr}$ and ${}_{}{}^{88}{}_{}{}^{}\mathrm{Sr}$ are determined and the $T_{<}$ states of ${}_{}{}^{89}{}_{}{}^{}\mathrm{Y}$ are studied.

NUCLEAR REACTIONS ${}_{}{}^{86,87,88}{}_{}{}^{}\mathrm{Sr}\mathrm{}(d,n)\mathrm{}$, $E_d=12\mathrm{}$ MeV; measured angular distributions. Deduced spectroscopic factors, ground state configurations. Enriched targets.