In terms of the effective two-body interaction, a general understanding of the limit of neutron stability of exotic nuclear systems has been attempted. The maximal $\frac{N}{Z}$ ratio has been calculated for various Skyrme interactions and compared with the predictions of Garvey and Kelson.

NUCLEAR STRUCTURE Neutron stability; exotic nuclei; Skyrme interaction.

The dependence of the rms radius of the deuteron cluster in ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ on the relative $d-\alpha$ momentum was investigated on the basis of the three-body wave function given by Rai, Lehman, and Ghovanlou.

NUCLEAR STRUCTURE $p-n$ relative wave function, cluster contraction.

Charge-exchange reactions on $N>Z$ targets can excite unnatural-parity states of stretched configurations which are not analogs of states excited in ($e,e^{\prime }$) and ($p,p^{\prime }$) reactions. This "new" class of stretched states is based on a proton-particle, neutron-hole configuration with both the particle and the hole in the same shell. A state of this type ($0\hslash \omega$) with a major configuration of ${(\pi f_{\frac{7}{2}},\nu f_{\frac{7}{2}}^{}{}_{}{}^{-1\mathrm{}})}_{7^{+}}$ is observed to be strongly excited in the ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}\mathrm{}(p,n)\mathrm{}{}_{}{}^{48}{}_{}{}^{}\mathrm{Sc}$ reaction at 160 MeV; however, no evidence is found for $1\hslash \omega$ stretched states based on ${(\pi g_{\frac{9}{2}},\nu f_{\frac{7}{2}}^{}{}_{}{}^{-1\mathrm{}})}_{8^{-}}$ or ${(\pi f_{\frac{7}{2}},\nu d_{\frac{5}{2}}^{}{}_{}{}^{-1\mathrm{}})}_{6^{-}}$ configurations.

NUCLEAR REACTIONS ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}\mathrm{}(p,n)\mathrm{}$, $E=160\mathrm{}$ MeV; measured neutron spectra at angles between 0° and 48.5°; extracted $\sigma \left(\theta \right)$ for the $7^{+}$ state of ${}_{}{}^{48}{}_{}{}^{}\mathrm{Sc}$ at $E_x=1.096\mathrm{}$ MeV; compared angular distribution with DWIA calculation based on nucleon-nucleon effective interaction.

The effect of the chemical state on the decay constant $\lambda$ of the $\beta$ emitter ${}_{}{}^{77}{}_{}{}^{}\mathrm{As}$ has been investigated by means of a differential ionization chamber. The result of the measurement is $\lambda \left(\mathrm{metallic} {}_{}{}^{77}{}_{}{}^{}\mathrm{As}\right)-\lambda \left({\mathrm{Ag}}_3{}_{}{}^{77}{}_{}{}^{}\mathrm{As}{\mathrm{O}}_4\right)=(0.93\mathrm{}\pm 0.44)\times {10}^{-4\mathrm{}}\lambda$.

RADIOACTIVITY ${}_{}{}^{77}{}_{}{}^{}\mathrm{As}$, measured $T_{\frac{1}{2}}$, double ionization chamber, chemical effect.

The differential cross sections for the reactions ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}(d,\alpha ){}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ and ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}({}_{}{}^3{}_{}{}^{}\mathrm{He},p){}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ were measured at the incident energies of 33.0 and 27.5 MeV, respectively, in order to investigate the structure of ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ in connection with the nuclei ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ and ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$. The angular distributions and the relative magnitudes of the cross sections were analyzed by using the distorted-wave Born approximation theory of the two-nucleon transfer reactions. The shapes of the calculated angular distributions reproduced well the experimental data. The transferred angular momenta $L$ extracted from the angular distributions were consistent with the spins and parities already known. A qualitative picture of the structure of the nucleus ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ from the data of the relative transition strengths of the two-nucleon transfer reactions was attempted using two simple models of nuclear structure, the Nilsson model with pairing correlations and the simple pairing model of a spherical nucleus. In the former the final state was described by a single configuration of two Nilsson quasiparticles and in the latter, by a single configuration of two quasiparticles in a spherical basis. This Nilsson model showed that the two-nucleon transfer strengths for the low-lying states of ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ supported the idea that there exist states with opposite signs of the deformation parameter in the low-lying states of ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$. The simple pairing model predicted well the overall features of the two-nucleon transfer strengths. This success evolved from the assumption that the final states of ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ were described separately for stripping to ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ and pickup from ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ by using realistic values of the occupation number probabilities for the shell model orbitals of the respective nuclei. These facts suggest also the existence of states with different character in the ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ nucleus.

NUCLEAR REACTIONS ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}(d,\alpha ){}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$, $E_d=33.0\mathrm{}$ MeV and ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}({}_{}{}^3{}_{}{}^{}\mathrm{He},p){}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$, $E_{{}_{}{}^3{}_{}{}^{}\mathrm{He}}=27.5\mathrm{}$ MeV; measured $\sigma (E_{\alpha },\theta )$ and $\sigma (E_p,\theta )$; enriched ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ and ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ targets. DWBA analysis, deduced $L$, $J^{\pi }$. Analysis with Nilsson model with pairing correlation and simple pairing model of spherical nucleus.

We discuss the problem of scalar wave multiple scattering in one dimension on a target of $n$ identical fixed scatterers with delta-function potentials. We consider in detail a statistical ensemble of configurations of scatterers whose positions are uniformly distributed throughout the scattering region. We succeed in analytically performing a configurational average (over all scatterer positions) for the wave function for the problem of a transmitted wave with constant amplitude. We discuss the relationship between this problem and the standard problem of an incident wave with constant amplitude. From the simple closed form for the average of the wave function, the optical potential for the system is obtained. We then present the large and small incident particle wavelength limits [with respect to the length ($L$) of the scattering region] for both the average of the wave function and the optical potential. We also examine the question as to where the optical potential can be approximated by the form it takes in the limit of infinite $n$. (The question of where in parameter space this occurs and how well the transmitted and reflected waves can be predicted with this form is discussed in the following paper.) Furthermore, we consider the large incident particle wave number limit for the average wave function and the optical potential for a general distribution of the scatterer positions in the limit of both $n$ and $L$ approaching infinity but with $\frac{n}{L}$ remaining fixed. Lastly, knowing the simple closed form for the average of the wave function, we prove that the effective field approximation becomes exact in the limit of infinite $n$ with all other parameters held fixed.

NUCLEAR REACTIONS Multiple scattering, randomly distributed point scatterers, one dimension; configurational average wave function, optical potential; low and high energy limits.

In the first paper of this series, we studied the problem of scattering in one dimension of a wave interacting with $n$ randomly distributed pointlike scatterers by delta-function potentials. Averaging the wave function for a constant amplitude transmitted wave over an ensemble of configurations allowed us to obtain an analytic expression for the optical potential which, in certain limits, took the form of the scatterer density $\rho$ times the scattering strength $\Gamma$. We examine the domain in parameter space where $\rho \Gamma$ can be regarded as a good approximation to the optical potential for both this problem and the problem in which the amplitude of the incident wave is constant. The conditions on the parameters are found to be the same in both the preceding problems. We then supplement $\rho \Gamma$ by an appropriate imaginary part. The wave function predicted from this effective potential approximation to the optical potential is in good agreement with that from the exact solution.

NUCLEAR REACTIONS Multiple scattering, $n$ randomly distributed point scatterers, one dimension; determination of parameter domain where optical potential is $\rho \Gamma$; parameters are $\rho$ (number density), $\Gamma$ (scattering strength); transmitted and reflected waves.

The effect of the Coulomb distortion of the strong interaction is studied on the basis of nucleon-nucleon observables. In particular, cross sections, polarizations, spin-correlation parameters, and spin-transfer coefficients are considered for proton-proton as well as neutron-neutron scattering at laboratory kinetic energies $E_{\mathrm{lab}}=10,20, \mathrm{and} 50$ MeV. The calculations are performed for the meson-theoretical Paris potential, the nonlocal separable Graz potential, and also using the Arndt-Hackman-Roper parametrization of proton-proton scattering phase shifts.

NUCLEAR REACTIONS $N-N$ interaction; Coulomb corrections in polarization observables.

Differential cross sections for proton scattering to the first three levels of the ground-state ($0^{+}$,$2^{+}$,and $4^{+}$) and $\gamma$ ($2_{\gamma }^{+},3_{\gamma }^{+},4_{\gamma }^{+}$) bands of ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$ have been measured at $E_p=20.37\mathrm{}$ MeV. These data, together with similar ones on ${}_{}{}^{24,26}{}_{}{}^{}\mathrm{Mg}$ available in the literature, have been analyzed by means of coupled channel calculations in which a hexadecapole vibrational term, accounting for direct excitation of the $4_{\gamma }^{+}$ state, is added to the asymmetric rotor model. Satisfactory fits have been obtained for all the transitions considered except the $3_{\gamma }^{+}$ cross sections; for ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ these remain unfitted even if contributions from a direct spin-flip mechanism are added incoherently. The importance of the "missing" contributions in the excitation of the $3_{\gamma }^{+}$ levels is estimated for the three nuclei considered.

NUCLEAR REACTIONS ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}(p,p^{\prime })$, $E_p=20.37\mathrm{}$ MeV; measured $\frac{d\sigma }{d\Omega }$ for 6 levels, coupled channel analyses for ${}_{}{}^{24,26}{}_{}{}^{}\mathrm{Mg}$ and ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$; deformed vibrational model; deduced deformation parameters.

A high-efficiency, high-resolution polarimeter has been employed to measure the transverse spin-flip probability in ($p,p^{\prime }$) reactions induced by polarized protons in the energy range from 30 to 42 MeV. The spin-flip probability for central forces is shown to be uniquely related to spin transfer ($s=1\mathrm{}$) in the eikonal approximation. More exact calculations indicate the general rule $S\ge 0.5$ when $s=1\mathrm{}$ and $S\le 0.1$ when $s=0\mathrm{}$. Antisymmetrized distorted-wave calculations give a generally poor account of spin transfer in isoscalar transitions and transitions in odd mass nuclei. Spin flip in isovector transitions is well described by the calculations.

NUCLEAR REACTIONS ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}(p,p^{\prime })$, $E_p=31,32,35.5,40,42$ MeV, measured spin-flip probabilities.

Using sources of ${}_{}{}^{24}{}_{}{}^{}\mathrm{Na}$, differential cross sections for elastic scattering of 2.754 MeV photons have been measured for angles between 60 and 120° and charge numbers of 30, 42, 50, and 58 with an accuracy of 2.8% on the average. For the cases covered by experiment, Delbrück scattering amplitudes have been calculated on the basis of the lowest-order Feynman graphs with an average numerical accuracy of 1%. For the same cases Rayleigh scattering amplitudes have been calculated on the basis of the second-order $S$ matrix using Dirac-Hartree-Fock-Slater wave functions. These investigations confirm the lowest-order Delbrück theory with an accuracy of 5%. This corresponds to a new test of vacuum polarization of the order $\alpha {\left(Z\alpha \right)}^2$.

NUCLEAR REACTIONS Photon scattering Zn, Mo, Sn, $\mathrm{Ce}(\gamma ,\gamma )$, $E=2.754\mathrm{}$ MeV: measured $\frac{d\sigma }{d\Omega }\left(\theta \right)$, $\theta =60\mathrm{}°-120°$; deduced test of Delbrück scattering.

We show that the two different formulations of the $\mathrm{NN}-\pi \mathrm{NN}$ system proposed by Afnan-Blankleider and Stingl-Stelbovics lead to a set of three linear coupled operator equations which are identical in form to the Faddeev equations. The resulting equations include the fact that both nucleons are identical and either can emit a pion. They also have dressing for the $\pi \mathrm{NN}$ vertex and $\mathrm{NN}$ and $\pi \mathrm{NN}$ propagators. The final equations are shown to satisfy two-and three-body unitarity.

NUCLEAR REACTIONS Feddeev-type equation for $\mathrm{NN}-\pi \mathrm{NN}$ system, proof of two- and three-body unitarity.

Photon strength functions have been derived from discrete neutron resonance data for electric and magnetic dipole radiation using the methods of slow neutron time-of-flight spectroscopy. The data cluster reasonably well around strengths of $b\left(E1\mathrm{}\right)\mathrm{}\cong 0.04$ Weisskopf units/MeV and $b\left(M1\mathrm{}\right)=1.4\mathrm{}$ Weisskopf units/MeV, respectively.

NUCLEAR REACTIONS Measured ${\Gamma }_{\gamma \mathrm{if}}$, $J$, $\pi$, $\sigma (n,\gamma )$; derived $〈{\Gamma }_{\gamma \mathrm{if}}〉$, $\frac{\Gamma }{D\left(E1\mathrm{}\right)\mathrm{}}$, $\frac{\Gamma }{D\left(M1\mathrm{}\right)\mathrm{}}$).

Differential cross sections and vector analyzing powers have been measured for ($\overrightarrow{d},t$) reactions induced on ${}_{}{}^{68}{}_{}{}^{}\mathrm{Zn}$ and ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}$ at $E_d=12.0\mathrm{}$ MeV and on ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$ and ${}_{}{}^{53}{}_{}{}^{}\mathrm{Cr}$ at $E_d=11.0\mathrm{}$ MeV. Transitions with $l=0,1,2,3, \mathrm{and} 4$ were observed. The analyzing power measurements for $l=1\mathrm{}$ transitions exhibit a strong, systematic dependence on $Q$ value, in addition to the expected $j$ dependence. Distorted-wave Born approximation calculations generally do not reproduce the ($\overrightarrow{d},t$) analyzing power data quantitatively, but do account qualitatively for the observed $Q$ dependence. A conclusive analysis of data for the odd-$A$ targets, aimed at determining the relative contributions of different $j$ values to mixed-$j$ transitions, has been possible only in those cases where empirical "calibration curves" for the analyzing powers could be drawn from results of single-$j$ transitions of appropriate $l$, $j$, and $Q$. A number of previous spin and parity assignments are confirmed and two new definite assignments are made on the basis of the present data.

NUCLEAR REACTIONS ${}_{}{}^{53}{}_{}{}^{}\mathrm{Cr}$, ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}(\overrightarrow{d},d)$, $E=11.0\mathrm{}$ MeV; ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}$, ${}_{}{}^{68}{}_{}{}^{}\mathrm{Zn}(\overrightarrow{d},d)$, $E=12.0\mathrm{}$ MeV; measured vector analyzing power $i{T}_{11}\left(\theta \right)$, cross section $\sigma \left(\theta \right)$; deduced deuteron optical model parameters. ${}_{}{}^{53}{}_{}{}^{}\mathrm{Cr}$, ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}(\overrightarrow{d},t)$, $E=11.0\mathrm{}$ MeV; ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}$, ${}_{}{}^{68}{}_{}{}^{}\mathrm{Zn}(\overrightarrow{d},t)$, $E=12.0\mathrm{}$ MeV; measured $i{T}_{11}(E_t,\theta )$, $\sigma (E_t,\theta )$. ${}_{}{}^{52}{}_{}{}^{}\mathrm{Cr}$, ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{63}{}_{}{}^{}\mathrm{Ni}$, ${}_{}{}^{67}{}_{}{}^{}\mathrm{Zn}$ levels deduced spectroscopic factors, $J$, $\pi$. Enriched targets.

The ${}_{}{}^{194,196,198}{}_{}{}^{}\mathrm{Pt}(p,p^{\prime })$ reactions have been studied at a proton energy of 35 MeV using nuclear emulsion plates and a high-resolution position-sensitive proportional counter. Approximately 45 levels were populated in each reaction. In ${}_{}{}^{198}{}_{}{}^{}\mathrm{Pt}$, 38 of 44 levels to about 3.2 MeV are reported for the first time. Angular distributions from 20° to 110° were measured for many of these levels. Several new $J^{\pi }$ assignments were made using empirical shapes of transitions to well-known levels in Pt. The results for the $J^{\pi }=0^{+},2^{+},4^{+} \mathrm{and} \left(\mathrm{for} {}_{}{}^{194}{}_{}{}^{}\mathrm{Pt}\right)6^{+}$ members of the ground band and the $2^{+}$, $3^{+}$, and $4^{+}$ members of the "quasi-$\gamma$" band were analyzed by coupled channels calculations incorporating relative transition strengths from the interacting boson approximation model. The multipole moments of the deformed optical model potential were calculated and compared to moments deduced from other studies.

NUCLEAR REACTIONS ${}_{}{}^{194}{}_{}{}^{}\mathrm{Pt}(p,p^{\prime })$, ${}_{}{}^{196}{}_{}{}^{}\mathrm{Pt}(p,p^{\prime })$, ${}_{}{}^{198}{}_{}{}^{}\mathrm{Pt}(p,p^{\prime })$, $E_p=35\mathrm{}$ MeV; measured $\sigma (E_p,\theta )$; deduced energies, $J^{\pi }$; coupled channels calculations, interacting boson approximation model; deduced optical model and deformation parameters, quadrupole and hexadecapole moments; comparisons to Coulomb excitation, ($\alpha ,{\alpha }^{\prime }$), and (${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$′); enriched targets, nuclear emulsion plates (7 keV FWHM) and position-sensitive proportional counter (15 keV FWHM), magnetic spectrograph.

The neutron-capture cross sections for ${}_{}{}^{186,187,188,189,190,192}{}_{}{}^{}\mathrm{Os}$ have been measured by the neutron-time-of-flight technique from 0.5 eV to 150 keV. Nuclear level spacings were extracted from the low-energy (resonance-region) data below ∼1 keV, and average cross sections from the data above 1 keV. The ratio of the Maxwellian-weighted average cross sections for ${}_{}{}^{186}{}_{}{}^{}\mathrm{Os}$ and ${}_{}{}^{187}{}_{}{}^{}\mathrm{Os}$ near 30 keV is a vital parameter for the determination of the duration of nucleosynthesis prior to the formation of the solar system, and thus for the determination of the age of the universe by the nuclear-dating technique. The present result of ${10.8}_{-2.2\mathrm{}}^{+1.4\mathrm{}}$×${10}^9$ yr for the duration of nucleosynthesis is in concordance with the value obtained from U-Th dating. The result for the age of the universe (17±3×${10}^9$ yr) agrees with the value obtained from the globular-cluster method, but clearly exceeds the most recent determination of the Hubble time.

NUCLEAR REACTIONS ${}_{}{}^{186,187,188,189,190,192}{}_{}{}^{}\mathrm{Os}(n,\gamma )$, $E=2\mathrm{}-1.5\times {10}^5$ eV; measured $\sigma (n,\gamma )$, Maxwellian-averaged $\sigma (kT=30\mathrm{} \mathrm{KeV})$; extracted average level spacing; deduced age of universe for Re-Os clock.

The level structures of the light lead nuclei ${}_{}{}^{195}{}_{}{}^{}\mathrm{Pb}$, ${}_{}{}^{197}{}_{}{}^{}\mathrm{Pb}$, ${}_{}{}^{199}{}_{}{}^{}\mathrm{Pb}$, and ${}_{}{}^{201}{}_{}{}^{}\mathrm{Pb}$ have been studied by in-beam $\gamma$-ray spectroscopy in bombardments of isotopically enriched HgO targets with ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ ions. The measurements included $\gamma$-ray singles, comprehensive ($\gamma \gamma t$) coincidences, half-life determinations, and $\gamma$-ray angular distributions. High-spin level spectra above previously known ${13/2}^{+}$ isomers are reported for the four nuclei, and are interpreted in terms of the weak coupling of an $i_{\frac{13}{2}}$ neutron hole to established states of the adjacent even-$A$ core nuclei.

NUCLEAR REACTIONS ${}_{}{}^{200,198}{}_{}{}^{}\mathrm{Hg}(\alpha ,3n)$, $E=35\mathrm{}-45$ MeV, ${}_{}{}^{198}{}_{}{}^{}\mathrm{Hg}({}_{}{}^3{}_{}{}^{}\mathrm{He},4n)$, $E=38\mathrm{}$ MeV, ${}_{}{}^{198}{}_{}{}^{}\mathrm{Hg}({}_{}{}^3{}_{}{}^{}\mathrm{He},6n)$, ${}_{}{}^{199}{}_{}{}^{}\mathrm{Hg}({}_{}{}^3{}_{}{}^{}\mathrm{He},7n)$, $E=74\mathrm{}$ MeV; measured $E_{\gamma }$, $I_{\gamma }\left(\theta \right)$, $\gamma -\gamma$ coin, $\gamma -t$ relationships; ${}_{}{}^{195,197,199,201}{}_{}{}^{}\mathrm{Pb}$ deduced high-spin levels, $J$, $\pi$, $T_{\frac{1}{2}}$.

The ${}_{}{}^{194,196,198}{}_{}{}^{}\mathrm{Pt}\mathrm{}(t,p)\mathrm{}$ reactions have been measured with 17 MeV tritons on enriched and natural Pt targets. The level structure of ${}_{}{}^{200}{}_{}{}^{}\mathrm{Pt}$ is probed for the first time, and several new excited ${\mathrm{O}}^{+}$ states have been identified in ${}_{}{}^{196,198,200}{}_{}{}^{}\mathrm{Pt}$. Systematics in level structure of ${}_{}{}^{192-200}{}_{}{}^{}\mathrm{Pt}$ are fairly constant, although there is evidence that ${}_{}{}^{198,200}{}_{}{}^{}\mathrm{Pt}$ are becoming more vibrational in structure, with the $\gamma$-unstable shape of the lighter Pt nuclides becoming more oblate-like. Systematics of $L=4\mathrm{}$ strengths are considered and can be qualitatively understood. The ($t,p$) strengths measured in the present study are combined with earlier $\mathrm{Pt}\mathrm{}(p,t)\mathrm{}$ and $\mathrm{Os}\mathrm{}(t,p)\mathrm{}$ measurements and compared with the systematics of two-neutron transfer strengths predicted by the interacting boson approximation, schematic, boson expansion, and pairing vibration models.

NUCLEAR REACTIONS ${}_{}{}^{194,196,198}{}_{}{}^{}\mathrm{Pt}\mathrm{}(t,p)\mathrm{}$, $E=17\mathrm{}$ MeV; enriched targets; measured energy levels, $\sigma \left(\theta \right)$ in ${}_{}{}^{196,198,200}{}_{}{}^{}\mathrm{Pt}$; DWBA.

NUCLEAR STRUCTURE $L=4\mathrm{}$ transitions, interacting boson approximation model, schematic model, boson expansion technique, pairing vibration model.

Differential cross sections have been measured for transitions to low-lying states in ${}_{}{}^{193}{}_{}{}^{}\mathrm{Ir}$ in the ${}_{}{}^{194}{}_{}{}^{}\mathrm{Pt}(d,{}_{}{}^3{}_{}{}^{}\mathrm{He}){}_{}{}^{193}{}_{}{}^{}\mathrm{Ir}$ reaction at $E_d=50\mathrm{}$ MeV. Transferred orbital angular momenta $l$ and spectroscopic factors have been deduced by comparison with zero-range distorted-wave Born-approximation calculations. The deduced spectroscopic factors give further evidence for the presence of the supersymmetric structure in nuclei in the plantium region, which has been recently pointed out by Iachello. The spin-parity of a state at $E_x=0.964\mathrm{}$ MeV has been assigned to be ${1/2}^{+}$.

NUCLEAR REACTIONS ${}_{}{}^{194}{}_{}{}^{}\mathrm{Pt}(d,{}_{}{}^3{}_{}{}^{}\mathrm{He}){}_{}{}^{193}{}_{}{}^{}\mathrm{Ir}$, $E=50\mathrm{}$ MeV, measured $\sigma \left(\theta \right)$, resolution 30 keV. DWBA analysis, deduced $l$ and $S$.