We present dispersion curves and field amplitudes for a plasma layer in a magnetic field. Various effects such as the nonreciprocal character of the dispersion, the pileup of bulk states at ${\omega }_{\infty }$, and the existence of surface states above ${\omega }_{\infty }$ should be observable in optical experiments.

We describe a new calculation of hyperfine contact interactions for ${\mathrm{Si}}^{29}$ lattice nuclei near shallow donors in silicon. The calculation utilizes Bloch functions for several energy bands throughout the Brillouin zone. The results are sufficiently accurate that for the first time it is possible to assign all experimental ${\mathrm{Si}}^{29}$ electron-nuclear double-resonance data to specific lattice sites.

The soft-x-ray $M_{2,3}$ emission spectrum of Fe has been measured below (560°C, $\frac{T}{T_c}=0.8\mathrm{}$) and above (840°C, $\frac{T}{T_c}=1.07\mathrm{}$) the Curie point, and has revealed motion of distinct structural features within the $d$ bands on passing through $T_c$. The results, taken with earlier photoemission data on Fe and Ni, are in excellent numerical agreement with, while in no sense providing verification of, the band ferromagnetism description of Stoner, Wohlfarth, and Slater for these metals.

We report a detailed study of the inelastic scattering reaction ${}_{}{}^{206}{}_{}{}^{}\mathrm{Pb}(p,p^{\prime }){}_{}{}^{206}{}_{}{}^{}\mathrm{Pb}_{}^{*}{}_{}{}^{}\left(2_1^{}{}_{}{}^{+}\right)$ for incident proton energies in the range from 14.2 to 17.3 MeV. It has been found possible to reproduce the experimental results quantitatively using a theoretical analysis incorporating a number of resonant compounds, as well as direct inelastic, scattering amplitudes. Interference effects play an important role and predictions of shell and weak-coupling models are found to be in excellent agreement with the experimental data.

Ultrarelativistic geodesic particle orbits in the Schwarzschild geometry produce radiation (GSR) with angular distributions like that of synchrotron radiation. The spectra of high-frequency scalar, electromagnetic, and gravitational GSR are compared to each other and to the spectrum of synchrotron radiation. The differences among the spectra are explained in terms of the shape of the effective potential for GSR and the inapplicability of geometric optics.

We report the measurement of the frequency of the 633-nm red laser line. This is the first measurement of an optical frequency in the visible range without reference to the speed of light or to a measured wavelength. Combination of the optical frequency with the known wavelength yields $c$ to an accuracy higher than previously known. This method demonstrates the practicability of a single-standard time-length measurement system unified via a defined value of the speed of light.

We have measured fine-structure splittings in atoms formed by antiprotons with both lead and uranium. Since the fine structure is produced by an interaction between the magnetic moment of the antiproton and the Coulomb field of the nucleus, a value for the magnetic moment can be derived from the observed splitting. We find a magnetic moment of - 2.83 ± 0.10 nuclear magnetons which agrees with the $\mathrm{TCP}$ prediction.

We present the results of an experimental study of the enhancement of the effective mass and its dependence on electron density. The study of this phenomenon in a two-dimensional electron gas, whose density may be varied continuously, allows for the first time a comparison for different values of $r_s$ within the same material.

We propose a simple general-model pseudopotential, which is in good agreement with the real potential of metal ions, especially in the range $q<~2k_{\mathrm{F}}$.

We have observed a peak in the inelastic light scattering of CdS in high magnetic fields at an energy slightly less than twice the bound electron spin-flip energy $\mu \mathrm{gH}$. The intensity, selection rules, field dependence, and binding energy of this process cannot be explained as second-order scattering. At very high excitation energies ($>~1$ MW/${\mathrm{cm}}^2$) the single spin-flip scattering becomes stimulated, with a sharp threshold and high conversion efficiency.

Considering the lowest-order electron-light coupling, we present a theory of multiple spin-flip ($\Delta S=n$; $n=2,3,\cdots$) Raman scattering based on the interaction of impurity spin states with virtual bound exciton states. The strength for the $\Delta S=n$ process is strongly magnetic field dependent and becomes comparable to the $\Delta S=1\mathrm{}$ case at low fields. The $\Delta S=n$ peak is at slightly lower energy than the $n$th overtone energy. These predictions may be checked experimentally.

We point out the possibility that the potentially important dielectric effect first considered by Gor'kov and Eliashberg for minute metallic particles may well occur in the recently identified one-dimensional metals formed by the mixed-valency planar complex compounds of Pt. Our idea is conditional on the validity of a recently proposed model of interrupted metallic strands.

The quadrupole interaction of ${\mathrm{Cd}}^{111}$ ions following the decay of ${\mathrm{In}}^{111}$ implanted by ($\alpha ,2n$) reactions into a cubic (fcc) Ag lattice has been measured with the time-differential perturbed angular correlation method. In addition to a smeared-out quadrupole interaction with a centroid frequency of ${\overline{\omega }}_Q\simeq 2.5$ MHz, about 10% of the implanted ${\mathrm{Cd}}^{111}$ ions experience a unique quadrupole interaction with $\omega _Q^{}{}_{}{}^0=115,130, or 140$ MHz, depending on the primary $\alpha$ beam. Annealing causes the quadrupole perturbation to vanish completely.

We report the first observation of pure nuclear quadrupole resonance in a vitreous material. The 7-MHz-wide ${\mathrm{As}}^{75}$ nuclear-quadrupole-resonance spectrum in vitreous ${\mathrm{As}}_2$${\mathrm{S}}_3$ is interpreted as indicating a distribution of pyramidal apex bond angles of half-width less than 2°.

The electron densities associated with the molecular complex used previously to explain the quadrupole coupling constants of ${\mathrm{Fe}}^{57}$ have been shown to explain consistently the isomer shifts for equivalent iron sites in ${\mathrm{Fe}}_2$${\mathrm{O}}_3$ and two inequivalent iron sites in several rare-earth iron garnets as well. The relative change in the charge radius of ${\mathrm{Fe}}^{57}$ nucleus has been deduced as -4.1 × ${10}^{-4\mathrm{}}$ (including relativistic effects).

We propose a theory which accounts for the linear magnetoresistance found in the transverse and longitudinal components in various metals. The theory is based on the existence of quasiperiodic static fluctuations, which have the anisotropy of the lattice and may be due to electron-phonon and/or electron-electron interactions. The fluctuations produce no noticeable change in the static properties of the metal but produce the dominant linear increase of the resistance at high magnetic fields.

A two-band model of a solid is presented which exhibits simultaneous first-order metal-nonmental and antiferromagnetic phase transitions in the Hartree-Fock approximation.

The new isotope ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ge}$ has been produced via the reaction ${}_{}{}^{64}{}_{}{}^{}\mathrm{Zn}({}_{}{}^3{}_{}{}^{}\mathrm{He},3n){}_{}{}^{64}{}_{}{}^{}\mathrm{Ge}$, chemically isolated, and its decay studied. Since ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ge}$ is therefore nucleon stable, it can in principle have an important role in the synthesis of mass 64 by $\alpha$ capture during explosive stellar events, as proposed by Arnett, Truran, and Woosley. However, from the measured half-life (62.3 ± 2.0 sec) and $\beta$-decay systematics, it appears that this mechanism is probably responsible for a negligible fraction of the observed abundance of mass 64.

The angular-momentum projection method is applied to the description of ($t,p$) and ($p,t$) reactions on deformed nuclei. The difference between the deformations of a target nucleus and that of a residual nucleus is taken into account in the calculation of the spectroscopic amplitude. The calculation is especially focused on the ground-state to ground-state ($p,t$) transitions. The neutron-number dependence of the calculated distorted-wave Born-approximation cross sections is in good agreement with the experimental results.

A generally covariant classical model for gravity, which in the limit of weak fields is essentially equivalent to Fujii's massive dilaton theory, is obtained when the invariance under a group of space-time-dependent geometry-preserving mass-unit transformations of a scalar-tensor theory is broken by ascribing a mass to the scalar field. The experimental consequences are discussed.