Mössbauer-effect measurements in external magnetic fields show that the magnetic structure of ferrimagnetic Ni${\mathrm{Fe}}_2$${\mathrm{O}}_4$ is the collinear Néel type. Ni${\mathrm{Fe}}_{0.3}$${\mathrm{Cr}}_{1.7}$${\mathrm{O}}_4$ is shown to have a triangular structure with ${\theta }_A=20\mathrm{}\pm 10°$ and ${\theta }_B=50\mathrm{}\pm 4°$.

A beat frequency in the oscillatory magnetoresistance of zincblende HgSe is interpreted as arising from the inversion-asymmetry splitting, which is shown to be about 0.007 eV at the Fermi level appropriate to 1×${10}^{18}$ electrons/${\mathrm{cm}}^3$.

We obtain the zero-field partition function and correlation functions of the one-dimensional, anisotropic classical Heisenberg model exactly and find similar results for an anisotropic "planar" spin model. The isotropic and the anisotropic cases have greatly different low-temperature behavior.

We generalize the recent solution of a model of two-dimensional ferroelectrics to include the addition of an arbitrary horizontal and an arbitrary vertical electric field and show that the general problem when all six vertex configurations have different energies, and when arbitrary horizontal and vertical electric fields are present is mathematically equivalent to the above problem.

Neutron particle-hole states in ${\mathrm{Ba}}^{138}$ have been observed in three different reactions: from the decay of isobaric analog resonances formed by the reaction ${\mathrm{Ba}}^{138}$+$p$, in the reaction ${\mathrm{Ba}}^{137}(d, p){\mathrm{Ba}}^{138}$, and as isobaric analog states in proton scattering from ${\mathrm{Ba}}^{137}$. It is thus possible to make reasonable assignments of spin and parity as well as to determine the shell-model configurations of many of these states.

High-resolution fast-neutron spectra (to about 1%) have been obtained by means of the proton-radiator method, detecting the proton recoils with solid-state detector telescopes and particle identifier circuits. Our spectra confirm a broad peak at 1.4 MeV and resolve another at 3.2-MeV excitation.

In a very low momentum ${K_L}^0$ beam, a sample of ${K_L}^0\to {\pi }^{\pm }{e}^{\mp }\nu$ decays has been identified in the 25-in. hydrogen bubble chamber by means of bubble density. Based on 531 events, the energy-dependence parameter for the ${K_{e3\mathrm{}}}^0$ vector form factor was determined by $\lambda =+0.01\mathrm{}\pm 0.015$, which is consistent with no energy dependence.

The total cross section for electron-positron annihilation into hadrons is examined under the assumption that the hadron electromagnetic current is a linear combination of vector-meson fields. A sum rule is found which implies that the cross section must fall off faster than $E^{-4\mathrm{}}{\left(\ln E\right)}^{-1\mathrm{}}$, where $E$ is the center-of-mass energy.

The meson-baryon total cross sections and elastic-scattering data in the forward direction are fitted using SU(3)-invariant $t$-channel amplitudes. The analysis implies that (1) $0<~{\sigma }_{\mathrm{tot}}(s\to \infty )<~15.5$ mb, and (2) $-0.11\mathrm{}<~\frac{\mathrm{Re}T(s, t=0)}{\mathrm{Im}T(s, t=0)}<~0$ as $s\to \infty$.

We show that the turbulent viscosity forces acting on photospheric meridional currents could cause the solar photosphere to be oblate by more than ±70 km. Although the sign of the effect is undetermined, this might remove the alleged discrepancy in Einstein's prediction for the perihelion advance of Mercury.

Using Bjorken's methods in the context of the recently proposed gauge-field algebra of currents, we discuss the problem of divergences in electromagnetic mass differences (${m_{{\pi }^{+}}}^2-{m_{{\pi }^0}}^2$, ${m_{K^{+}}}^2-{m_{K^0}}^2$) and decays, weak decays (e.g., ${K_1}^0\to 2\pi$), and asymptotic behavior of electromagnetic processes.

Toller's group-theoretical analysis of kinematics is exploited to define a complete set of variables, each of independent range, for particle production of arbitrary multiplicity. In terms of these variables, the generalized Regge-pole hypothesis leads to a simple, unambiguous, and experimentally accessible prediction for high-energy multiple-production cross section. A flat Pomeranchuk trajectory is shown to violate the Froissart bound.

The temperature dependence of far-infrared collision-induced absorption of rare-gas mixtures is shown theoretically to be capable of providing detailed information about the repulsive part of the interaction potential for unlike atoms. Two common potentials which give virial coefficients differing by only 3% over a large temperature range should show absorption differing by 30%.

The resonance fluorescence of a system of two identical, interacting atoms is investigated when the atoms are separated by distances that are large compared with atomic size. We consider the interactions between the atoms and the radiation field and the electrostatic interaction between the atoms, and find that the line shape of the emitted radiation consists of two peaks whose amplitude, separation, and width are functions of the internuclear distance $R$ of the atoms. The peaks are distinct at smaller separations, and, as $R$ increases, rapidly merge to the characteristic line shape of a single, isolated atom.

We report the existence of substantial polarization effects, apparently involving the $2{}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}$ metastable state, produced by maintaining a discharge in a ${\mathrm{He}}^3$ sample which is placed in a magnetic field. A polarization of 0.06%, which corresponds to an enhancement of 2200, has been produced at 1 kG. A partially successful theoretical explanation is discussed.