The results of Glaberson and Steingart on vortex-core radii at low temperatures are analyzed from the point of view of a quasithermodynamic theory and found to be in agreement with the theory.

The anisotropy of the upper critical field $H_{c2\mathrm{}}$ of a noncubic superconductor was studied for the first time. A torque magnetometer was used to detect $H_{c2\mathrm{}}$ between 2 and 7°K as a function of orientation in a small single crystal of technetium. The relative anisotropy of $H_{c2\mathrm{}}$ consists of a large temperature-independent and possibly a small temperature-dependent part. The temperature-independent contribution can be attributed to the anisotropy of the effective mass.

High-resolution, divergent-beam x-ray diffraction photographs reveal previously unreported detail in multiple Borrmann (000), (111), (111) reflections undergoing anomalous transmission through perfect germanium crystals. These have been accounted for satisfactorily using the plane-wave formulation of the dynamical theory of x-ray diffraction.

The superconducting heat-capacity anomaly of intercalated Ta${\mathrm{S}}_2$ compounds is independent of the spacing between the Ta${\mathrm{S}}_2$ layers when the spacing is varied between 3 and 30 Å. We conclude that the entropy associated with the anomaly arises mainly from two-dimensional correlations.

Diamagnetic anisotropy associated with the transition into the superconducting state in intercalated Ta${\mathrm{S}}_2$ crystals is seen above 35°K. The anisotropy grows inversely with temperature obeying roughly a diamagnetic Curie law. It seems plausible to ascribe it to electron correlations which at lower temperature are responsible for the superconductivity.

Resonant light scattering by single-particle excitations was observed in $n-\mathrm{GaAs}$ with incident photon energies near the $E_0+{\Delta }_0$ optical energy gap. We find that under extreme resonance conditions the spectra have two components with the scattered light polarization perpendicular and parallel to the incident light. These results are interpreted in terms of a random-phase-approximation theory.

We have measured the "forbidden" (222) reflection of neutrons from silicon between 15 and 1353°C. We have used these measurements to correct the x-ray (222) structure factor for the anharmonic motion of the atoms. The scattering from the anticentrosymmetric valence charge density obtained in this way is found to be less temperature dependent than that from the core. We take this as evidence of the failure of the rigid-ion model.

Laser-induced fluorescence line narrowing of the ruby $R_1$ Zeeman spectra at 693.4 nm is reported using a continuous, stable, single-frequency ruby laser for resonant excitation. A resolution in excess of ${10}^7$ corresponding to a linewidth of ∼ 30 MHz has been achieved. The linewidths are anisotropic with respect to the relative magnetic-field-crystal-axis orientation and, at low Cr concentrations, are expected to be determined by Cr-Al superhyperfine interactions.

Tunneling at 4.2°K from lead into degenerate $n$-type GaSb under hydrostatic pressure exhibits huge changes when conduction-band extrema cross each other. In the indirect-gap configuration, strong phonon-assisted structures show up together with a typical resistance kink related to the onset of a (000) tunneling path. The measured interband pressure coefficient is -9.6 meV/kbar. All results suggest that the band crossing occurs 3 kbar higher than expected.

We report exact solutions of the equations of self-induced transparency which generalize the linear theory of refractive index up to theoretical peak intensities of ${10}^{15}$ W ${\mathrm{cm}}^{-2\mathrm{}}$. The refractive indices are real, and there is no dissipation from inhomogeneous broadening. We solve the dielectric-surface problem for these solutions. We note the possibility of regaining previous analytical solutions in a fashion which permits a slight extension and some critical examination of these.

The spin-wave dispersion relation $\hslash \omega \left(\overrightarrow{\mathrm{q}}\right)$ for the $c$ direction of erbium metal in its conical magnetic phase has been studied by coherent inelastic scattering of thermal neutrons. The improved resolution of the present experiment compared with that used in earlier work on Er has permitted the first observation of both the distinct spin-wave branches corresponding to $\hslash \omega (+\overrightarrow{\mathrm{q}})$ and $\hslash \omega (-\overrightarrow{\mathrm{q}})$ over a wide range of $\left|\overrightarrow{\mathrm{q}}\right|$ As a consequence these results are the first to indicate that the anisotropic exchange interaction is a dominant interaction for a rare-earth metal and/or the model magnetic Hamiltonian generally employed for these metals is seriously inadequate.

Ideas from Griffin's exciton model are combined with those from the nucleon-nucleon scattering approach to nuclear transition times to provide a simple closed-form expression for predicting pre-equilibrium decay phenomena, including variation of pre-equilibrium emission with target mass, excitation energy, and initial particle and hole numbers. Time estimates for pre-equilibrium emission are given at several excitations.

The concentric spherical cavity is used as a vehicle for study of the complete break-down of the "relativistic particle in a box" formula for the photon rest-mass effect. The results are applied to a determination of the limit on the photon's rest mass which can be inferred from the Schumann resonances.

We have studied antiproton-deuteron elastic scattering between 1.60 and 2.00 GeV/c incident momenta. The differential cross sections may be characterized by a very steep forward peak (with $b\sim 43$ ${\mathrm{GeV}}^{-2\mathrm{}}$) and a prominent break near $-t\sim 0.2$ ${\mathrm{GeV}}^2$. The results are used to test the validity of Glauber's multiple-scattering theory. Within the experimental range of measurements ($-t$ between 0.028 and 0.46 ${\mathrm{GeV}}^2$), the theory provides a good qualitative description of the data.

If the longitudinal structure function in inelastic lepton-nucleon scattering vanishes in the Bjorken scaling limit, then the dimension of each term in the scale-invariance-breaking Hamiltonian is ⩾ 3.

Double-particle exchange in hadronic interactions is investigated with an extension of our strong-absorption model. All parameters are taken from single-particle-exchange fits. Spin effects, variations in coupling values, and unavoidable cancelations result in a cross-section range of ∼ ${10}^5$ for different forward reactions, in good agreement with existing data. Reactions with exotic-quantum-number exchange are small because of spin and symmetry coupling properties of particles, while some nonexotic double-particle exchanges are quite large.

The quantitative predictions of an inclusive multiperipheral model are compared with the measured secondary spectra in $\mathrm{pp}$ collisions from 12 to 30 GeV/c.

A multichannel phase-shift analysis has been performed for the first time on the available experimental data of all the channels of $\overline{K}N$ interactions in the momentum region 0 to 1200 MeV/c. The Argand diagrams of the reaction amplitudes and the resonance parameters within the momentum region are given. The results provide stronger evidence for a number of previously suggested resonances and also indicate some new possible resonances.

The energy-differentiated electron impact spectra of ${\mathrm{H}}_2$ has been studied near the ${\mathrm{H}}_2^{+}$ threshold in a transmission experiment. Eleven structures with spacings characteristic of the ${}_{}{}^2{}_{}{}^{}\Sigma _{\mathrm{g}}^{}{}_{}{}^{}$ state of ${\mathrm{H}}_2^{-}$ have been found starting at about 13.6 eV. Five of these structures are above the ${\mathrm{H}}_2^{+}$ threshold. It is suggested that some of the structure previously found in the cross section for the production of ${\mathrm{H}}_2^{+}$ near threshold is due to autoionization of this state of ${\mathrm{H}}_2^{-}$.

Small-angle charge-exchange measurements are made on the ${\mathrm{He}}^{+}$ + ${\mathrm{N}}_2$ collision in an energy range from 0.50 to 3.00 keV and in an angular region out to 2.0°. The experimental results directly show that charge exchange plays a major role in the collision. At each energy the probability of charge exchange increases monotonically with increasing angle of scattering and then attains a relatively constant value with further increase in angle.