The spectroscopic data for even-parity rotational and intrinsic states in ${}_{}{}^{181}{}_{}{}^{}\mathrm{W}$ and ${}_{}{}^{187}{}_{}{}^{}\mathrm{Os}$ are shown to be incompatible with very large static nuclear hexadecapole deformations (${\epsilon }_4\cong 0.2$) implied by conventional analysis of recent Coulomb excitation measurements of $E4\mathrm{}$ transition moments in ${}_{}{}^{182}{}_{}{}^{}\mathrm{W}$ and ${}_{}{}^{186,188}{}_{}{}^{}\mathrm{Os}$.

An experiment is suggested to test the existence of a phase correlation for two space-separated superconductors. The phase in question is that of the eigenvalue of the operator $S$ that creates a pair in one superconductor and removes a pair from the other. This will also provide a clear-cut test for the charge and lepton number superselection rules.

The results of a study on vacuum polarization, orders $\alpha {\left(Z\alpha \right)}^n$, $n>~3$, for large-$Z$ systems encountered in heavy-ion collisions are presented. It is shown that the higher-order vacuum polarization cannot prevent the $1S_{\frac{1}{2}}$ state from reaching the lower continuum, $E=-m_e{c}^2$, for some critical charge $Z_{\mathrm{cr}}\sim 170$. In addition, the stability and localization of a heliumlike system for $Z>\mathrm{}{Z}_{\mathrm{cr}}$ is demonstrated.

A general way is demonstrated to derive Bäcklund transformations for nonlinear partial differential equations that are solvable by the inverse scattering method in the scheme of Ablowitz, Kaup, Newell, and Segur.

Proton and antiproton total cross sections on protons and deuterons have been measured at 50, 100, 150, and 200 GeV/c. The proton cross sections rise with increasing momentum. Antiproton cross sections fall with increasing momentum, but the rate of fall decreases between 50 and 150 GeV/c, and from 150 to 200 GeV/c there is little change in cross section.

Total cross sections of ${\pi }^{\pm }$ and $K^{\pm }$ on protons and deuterons have been measured at 50, 100, 150, and 200 GeV/c. All of the cross sections rise with increasing momentum.

The two limiting cases of dipole-allowed excitation transfer rates between molecules, $w\sim \frac{1}{R^3}$ (Perrin) and $w\sim \frac{1}{R^6}$ (Förster), where $R$ is the separation, may be obtained as well-defined limits of a single function $w\left(R\right)\mathrm{}$. The demonstration is based on a model which allows the interaction strengths and relaxation rates to be compared explicitly and which has a generalization describing the situation in real molecules.

We report a new technique for the measurement of short lifetimes (${10}^{-14\mathrm{}}$ sec) of innershell vacancies in heavy-ion projectiles moving through thin, solid targets. The technique is applicable whenever the yield of projectile x rays does not increase in proportion to target thickness. Lifetime values of 1.5×${10}^{-14\mathrm{}}$ and 3.3×${10}^{-14\mathrm{}}$ sec have been found for $K\alpha$ and $K\beta$ transitions, respectively, in highly stripped sulfur ions.

A set of equations is given, which allows us to rederive both the results of Leggett (hydrodynamic regime) and of Maki and Ebisawa (collisionless regime) for NMR in superfluid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$. The NMR linewidths for both transverse and longitudinal resonance are derived by introducing a relaxation-time approximation. The results are in good agreement with experimental data.

Recently developed renormalization-group techniques are summarized and exploited to yield a renormalization-group analysis of bicritical and tetracritical points (which arise in antiferromagnets and boson systems). For $n\lesssim 3$ an isotropic or Heisenberg fixed point dominates and gives bicritical behavior; but for $n\gtrsim 4$ a new "biconical" fixed point with irrational $\epsilon$-expansion coefficients appears. This describes a tetracritical point and may be relevant to displacive phase transitions.

We demonstrate the use of the $I_1$ luminescence feature in the near-bandgap luminescence spectrum of CdS as a high-resolution phonon spectrometer by measurement of the phonon distribution resulting from a photoexcited heat pulse generated in a gold film evaporated on the crystal.

We have determined the interconfiguration mixing ratios (${\mathrm{Sm}}^{+3\mathrm{}}$/${\mathrm{Sm}}^{+2\mathrm{}}$) of 1.4 and 4.1 for ${\mathrm{Sm}}_{0.81}$${\mathrm{Y}}_{0.19}$S and Sm${\mathrm{As}}_{0.18}$${\mathrm{S}}_{0.82}$ at 295 K from their x-ray photoemission spectra. These ratios are observed to decrease reversibly by a factor of 2 at 110 K. The agreement of these results with valences deduced from lattice-constant measurements is direct evidence that configuration mixing is responsible for the anomalous temperature- and composition-dependence of the lattice constant.

We show core-electron energy spectra determined by means of (soft) x-ray photoelectron spectroscopy and appearance potential spectroscopy to be closely related for $2p$ electrons in iron and nickel. An earlier comparison for the first transition-series elements had indicated a systematic difference between appearance-potential-spectroscopy data and tabulated values based on x-ray emission and hard-x-ray-excited x-ray photoelectron-spectroscopy data.

Quantum levels associated with the confinement of carriers in very thin, molecular-beam-grown ${\mathrm{Al}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$-GaAs-${\mathrm{Al}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$ heterostructures result in pronounced structure in the GaAs optical absorption spectrum. Up to eight resolved exciton transitions, associated with different bound-electron and bound-hole states, have been observed. The heterostructure behaves as a simple rectangular potential well with a depth of $\approx 0.88\Delta E_g$ for confining electrons and $\approx 0.12\Delta E_g$ for confining holes, where $\Delta E_g$ is the difference in the semiconductor energy gaps.

The spectral dependence of the Auger component of the uv photoemission and the far-uv reflectance show that the optical excitation of $5d$ core states cannot be described in terms of simple density of states indicating that matrix element effects must be included.

Cyclotron resonance of holes orbiting in the $a-b$ plane of an anthracene crystal has been observed. This represents the first time that this phenomenon has been observed in a molecular crystal. From these experiments, the hole effective mass is determined to be $11m_e$ where $m_e$ is the free-electron mass. The hole scattering time at 2°K was measured in two different crystals and found to be ∼7×${10}^{-11\mathrm{}}$ sec in one crystal and 4 ×${10}^{-10\mathrm{}}$ sec in the other.

The resistivity of nearly stoichiometric iron oxide was measured in the temperature range $78<~T<~300°$K. The temperature derivative of the resistivity, $\frac{d\rho }{\mathrm{dT}}$, in the vicinity of the critical temperature, $T_c$, was found to be proportional to ${\epsilon }^{-0.4\mathrm{}}$, where $\epsilon =\left|\frac{(T-T_c)}{T_c}\right|$. The results are explained by incorporating a normalized Ornstein-Zernike correlation function into the de Gennes-Friedel formula for critical scattering.

Simple asymptotic expressions are obtained for the optimum $Q$ value and for the total heavy-ion transfer cross section with optimum $Q$ value at energies well below the barrier. For such reactions transfer processes are predicted to be more important than compound reactions in agreement with measurements performed on the ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$ + ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ system. Calculations on transfer reactions between ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, of current interest in nucleo-synthesis, indicate direct reactions to be of no significance.

${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ elastic-scattering angular distributions have been measured at several energies, and an excitation function has been obtained at 70° center of mass from $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=17\mathrm{} \mathrm{to} 2.8$ MeV. The ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ data are greatly damped compared with ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ + ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ data in this energy range. This demonstrates that the absorption is not determined primarily by compound-nuclear properties. The differences are interpreted in terms of the more favorable angular-momentum matching conditions for the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ direct-reaction channels.

Angular distributions obtained in a study of the ${}_{}{}^{25}{}_{}{}^{}\mathrm{Mg}({}_{}{}^6{}_{}{}^{}\mathrm{Li}, d)$ reaction at $E_{\mathrm{Li}}=36\mathrm{}$ MeV are characterized by the lowest allowed $L$ transfers for cluster transitions to the members of the ground-state rotational band of ${}_{}{}^{29}{}_{}{}^{}\mathrm{Si}$, while a mixture of $L$ values is required for states of the $K={\frac{3}{2}}^{+}$ excited band. This demonstrates that an $\alpha$-transfer reaction can probe the internal structure of the nucleus in a way that can be deciphered.