From NMR relaxation studies, experimental and theoretical evidence is obtained for electron-spin pair-correlation effects in paramagnets.

Time-resolved Schlieren studies of the expansion of a laser-produced spark during the rising portion of the initiating laser pulse have been carried out in neon, argon, nitrogen, and air. The results obtained are not compatible with the radiation-supported shock-wave model, nor can they be explained in terms of a radiation transport wave or a simple breakdown wave. A satisfactory explanation involving a traveling ionization-breakdown wave is proposed.

Liquid-helium-temperature tunneling data for PbTe indium-doped $p-n$ junctions exhibit a series of sharp conductance increments with ∼5-mV spacing as well as the "zero-bias conductance minimum" and the LO-phonon shoulder at ∼13.8 mV. Indium-gallium alloyed junctions exhibit also a second series with ∼6.5-mV spacing. This periodic structure is attributed to the "inelastic scattering" of tunneling electrons by localized vibrational modes of the indium and gallium impurity atoms in the tunneling junction.

Light scattering from screened single-particle electron excitations has been observed in GaAs, InP, and CdTe. The intensity, polarization properties, and temperature dependence of the single-particle scattering in GaAs are compared with effective-mass calculations based on nonparabolic as well as parabolic bands. The experimental results are in disagreement with present theory.

Raman-scattering measurements on K${\mathrm{H}}_2$P${\mathrm{O}}_4$ reveal a broad, low-frequency ferroelectric mode which can be represented by a simple damped-harmonic-oscillator function. The resultant characteristic frequency and reciprocal zero-frequency susceptibility approach zero while the damping factor remains constant as $T$ approaches $T_c$ from above. At high $T$, the characteristic frequency approaches ∼99 ${\mathrm{cm}}^{-1\mathrm{}}$ and the linewidth, ∼170 ${\mathrm{cm}}^{-1\mathrm{}}$.

We report the observation of localized energy levels in the forbidden gap of PbTe by tunneling spectroscopy in PbTe-${\mathrm{Al}}_2$${\mathrm{O}}_3$-metal junctions. This study reveals the existence of deep centers in the neighborhood of the PbTe surface, in which the energies of major levels are approximately inversely proportional to $n^2$ ($n$ an integer, ≥3). Many of the levels show enormously large $g$ values (up to 18), which seem to suggest a mixing of these localized states with the bands in PbTe.

Measurements have been made of the vector analyzing power for polarized deuterons of 12 MeV of the reactions ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(d, p){}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(d, p){}_{}{}^{13}{}_{}{}^{}\mathrm{C}_{}^{*}{}_{}{}^{}$ (3.09-MeV state), and ${}_{}{}^9{}_{}{}^{}\mathrm{Be}(d, p){}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$. For the first of these reactions a comparison has been made with proton-polarization measurements at a nearby energy.

The differential cross section for elastic scattering of 600-MeV protons from ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ has been measured for laboratory angles between 4° and 44°. The data are analyzed in terms of the diffraction approximation of Glauber.

An investigation of the fine structure in the region of an intermediate resonance observed at $E_n\approx 0.36$ MeV in the scattering of neutrons from Fe reveals properties consistent with the interpretation of this resonance as a doorway state in the compound nucleus.

A classification of conspiring trajectories according to SU(3) symmetry, exchange degeneracy, and Lorentz symmetry is given. This classification gives rise to numerous experimental consequences. A few of such predictions are indicated.

We show that the ambiguities present in the current-algebra and partially conserved axial-vector current model of low-energy $\pi -\pi$ scattering are the same as those in the single-pion production amplitude. The experimental data strongly support the Weinberg formulation.

A connection is suggested between the ambiguities in the definition of the equal-time commutator [${{\dot{J}}_{\mu }}^{\mathrm{em}}(0, \overrightarrow{\mathrm{x}})$, ${J_{\nu }}^{\mathrm{em}}\mathrm{}\left(0\right)\mathrm{}$] and the experimental indications of an exponentially falling electromagnetic form factor for the nucleon. On this basis, a resolution is proposed of the difficulty of current-algebra models which appear to give divergent expressions for the electromagnetic mass shifts of hadrons.

We show a possible connection between a theorem due to Griffiths and a conclusion of van der Hoeven, Teaney, and Moruzzi about the critical magnetic properties of EuS.