The $K$-shell fluorescence yield has been calculated with the Hartree-Fock-Slater model for all multiply ionized states of neon. These results are compared with the recently measured average $K$-shell fluorescence yield for 30-MeV ${\mathrm{O}}^{7+}$ collisions with Ne. It is also shown that the commonly used statistical scaling procedure leads to significant errors for neon.

The diffusion coefficient of Brownian particles in the binary mixture nitroethane-iso-octane close to the critical phase transition has been measured using autocorrelation spectroscopy. The results support a logarithmic divergence in the shear viscosity.

The electron cyclotron drift instability has been observed in a controlled, steady-state experiment. Enhanced noise bands are seen in the first two Bernstein wave dispersion branches. Dispersion, noise frequency dependence upon magnetic field and ion beam velocity, and saturation are demonstrated.

It is found that nonlinear frequency shifts proportional to the square of the amplitudes of the waves may lead to a soliton-type solution in time for stabilized explosive instabilities.

The cross section for producing ${}_{}{}^{11}{}_{}{}^{}\mathrm{C}$ from carbon irradiated by 270-MeV/nucleon ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ has been found to be 90.0 ± 4.6 mb. The measurement was made using internal counting in plastic scintillators of three different thicknesses; the nitrogen beam was monitored by nuclear emulsions.

Within the context of the Strutinsky method, we obtain the effect of angular-momentum conservation on the nuclear deformation energy. In contrast to the results of Kelson and Shoshani, the correction to the fission barrier is found to be small (less than 200 keV) for all nuclei.

$\alpha$ particles in the energy range 11-18 MeV were used to excite the $2^{+}$ and $4^{+}$ members of the ground-state band in ${}_{}{}^{152}{}_{}{}^{}\mathrm{Sm}$. The measured excitation probabilities were analyzed in the framework of Coulomb excitation and the deformed optical model. The resulting electrical transition matrix elements and optical-model deformation parameters are $〈0^{+}\parallel m\left(E2\mathrm{}\right)\mathrm{}\parallel 2^{+}〉=(1.86\mathrm{}\pm 0.03)e$ b, $〈0^{+}\parallel m\left(E4\mathrm{}\right)\mathrm{}\parallel 4^{+}〉=(0.37\mathrm{}\pm 0.09)e$ ${\mathrm{b}}^2$, ${\beta }_2=0.214\mathrm{}\pm 0.007$, and ${\beta }_4=0.038\mathrm{}\pm 0.007$.

The intrinsic third-order intensity correlation function of a laser beam has been measured by a digital correlation technique, for a He: Ne laser operating near threshold. The results are compared with some recent calculations of Cantrell, Lax, and Smith and are found to be in good agreement.

We observe the reaction $\mathrm{dp}\to d\left(p{\pi }^{+}{\pi }^{-}\right)$ which allows no exchange of isospin between beam and target particles and therefore may approximate pure diffractive dissociation at this energy. The decay of the $p{\pi }^{+}{\pi }^{-}$ system is not azimuthally isotropic around its direction in the overall c.m. frame, vitiating its interpretation as a fireball. Both $s$- and $t$-channel helicity conservation fail for the process.

We show how a simple $t_{min}$ effect can significantly alter the ${\sigma }_n\sim \frac{1}{n^2}$ rule found in most diffractive models of particle production. Data on $\mathrm{pp}$, ${\pi }^{-}p$, and $K^{-}p$ collisions appear consistent with $n^2{\sigma }_n\sim \exp (-\frac{n^4}{s})$, which implies that (1) double diffraction dissociation is the dominant feature, and (2) $〈n〉\sim \ln s$, but correlation functions rise much more slowly than in earlier treatments. Critical comments on diffractive models are given.

A new mass formula for Kerr black holes is deduced, and is constrasted to the mass formula which is obtained by integrating term by term the mass differential and which consists of three terms interpreted, respectively, as the surface energy, rotational energy, and electromagnetic energy of the charged rotating black hole. A comparison is suggested between a rotating black hole and a rotating liquid drop which leads to a speculation that Kerr black holes may develop instabilities.

Time-differential perturbed angular correlation experiments on the excited nuclear levels of ${}_{}{}^{117}{}_{}{}^{}\mathrm{In}$ and ${}_{}{}^{111}{}_{}{}^{}\mathrm{Cd}$ in Cd compounds show that (i) $\beta$ decay and ($n, \gamma$) reaction aftereffects are absent, and (ii) the ratio of the quadrupole interaction frequency at the Cd and In sites in many cases is a constant independent of the structural type of the compound. We interpret this as evidence for the ionic nature of the Cd and In bonds and derive the quadrupole moment of the 247-keV level of ${}_{}{}^{111}{}_{}{}^{}\mathrm{Cd}$ to be $\mathrm{}\left|Q\right|=0.77\mathrm{}\left(12\right)\mathrm{}$ b.

Macroscopic inhomogeneities are observed in glassy ${\mathrm{Tl}}_2$Se${\mathrm{As}}_2$${\mathrm{Te}}_3$ using a contactlessconductivity technique. Electron microprobe experiments indicate that the samples are compositionally homogeneous and suggest that the inhomogeneities are structural. These inhomogeneities exhibit a thermally activated conductivity considerably greater than the dc bulk value but with an identical activation energy.

Iodine adsorbing on a silver (111) surface forms a $(\sqrt{3}\times \sqrt{3})30\mathrm{}°$ structure. The position of the adsorbed atoms within the unit cell of the surface layer has been determined by comparison of the measured curves of intensity versus energy of several low-energy electron diffraction spots with dynamical model calculations.

The optical absorption spectrum of the ferromagnetic insulator ${\mathrm{K}}_2$Cr${\mathrm{Cl}}_4$ has been measured from 8000 to 25 000 ${\mathrm{cm}}^{-1\mathrm{}}$ and for temperatures between 4.2 and 300°K.

The thermopower anomaly in the vicinity of the ferromagnetic critical point of Gd${\mathrm{Ni}}_2$ has been measured and found to be of the form predicted by the spin disorder scattering model proposed recently by Thomas, Levin, and Parks. These results allow a vivid comparison between the above model and the idea that the anomalous thermopower measures the static electron entropy in metals, which has been recently discussed by Tang, Kitchens, and Craig.

We report sufficient conditions for the validity of the inequality $E_0\mathrm{}\left(3\right)\mathrm{}\le 3E_0\mathrm{}\left(2\right)\mathrm{}$ for the ground-state energies of two and three nonrelativistic identical bosons interacting via spherically symmetric pair potentials.

Measurements are reported for the complete-fusion cross sections in the reactions of ${\mathrm{B}}^{11}$ + ${\mathrm{Tb}}^{159}$, ${\mathrm{C}}^{12}$ + ${\mathrm{Gd}}^{158}$, and ${\mathrm{O}}^{16}$ + ${\mathrm{Sm}}^{154}$ at bombarding energies such that the excitation energy of the ${\mathrm{Yb}}^{170}$ compound nuclei that are formed is 107 MeV. The results indicate that the complete-fusion cross sections are determined by dynamical processes in the entrance channel rather than by the equilibrium properties of the compound system.

Distortions of the plane texture of smectic-$A$ and cholesteric liquid crystals are shown to combine with the uniaxial birefringence of the plane texture to produce a strong characteristic light-scattering effect. We have observed static deformations, arising from surface defects, as well as dynamic deformations arising from thermal or mechanical stress. An immediate application of this effect is to confirm theoretical speculations on the elasticity of smectic-$A$ phases.

Polycarbonate and glass detectors exposed on Apollo 16 to the 17 April 1972 solar flare were used to measure the spectrum of iron-group cosmic-ray nuclei down to ∼0.02 MeV/nucleon. The enrichment of iron relative to lighter nuclei previously seen at higher energies increases markedly in this new, very-low-energy region. The energy spectrum of carbon and heavier nuclei inferred from sensitized Lexan polycarbonate reveals the enrichment of iron relative to carbon and heavier nuclei down to ∼0.03 MeV/nucleon.