Profiles of the $2s^2 \left({}_{}{}^1{}_{}{}^{}S\right)$ autoionizing state in He have been observed in the ejected-electron spectrum of ${\mathrm{H}}^{+}$ + He for small angles of ejection and for ${\mathrm{H}}^{+}$ energies of 6 to 150 keV. The shape parameter $q$ shows an increasing dependence on projectile energy as the angle of ejection is decreased, with strong, quasiperiodic oscillations appearing at 10°.

In the interaction of a $Q$-switched Nd-glass laser radiation with cesium vapor, the molecular cesium component seems to play an important role in the multiphoton ionization process at low laser intensity.

We have studied the effects of a weak electrostatic turbulence parallel to magnetic field lines on trapped particle motions in toroidal plasmas. We discuss possibilities of scattering of the trapped particles into the untrapped region of velocity space in the presence of ion sound turbulence.

Experiments with a curved $\theta$ pinch show that the application of an oscillating axial current suppresses the usual toroidal drift of the plasma column and allows a stable, dynamic equilibrium to be established.

We investigate ion-molecule charge exchange followed by dissociative electron recombination with molecular ions due to the presence of common impurities in a plasma-containment device. For a ${\mathrm{He}}^{+}$ plasma with ${\mathrm{N}}_2$ impurity, the ionic constituency of plasmas is changed from ${\mathrm{He}}^{+}$ to nitrogen ions with a time constant ${\tau }^{*}$ given by ${\tau }^{*}P\left({\mathrm{N}}_2\right)\simeq 24$ msec $\mu$ Torr. However, those ion-molecular recombination processes are not responsible for the enhanced plasma loss in the Princeton spherator at the best vacuum condition.

The afterglow of a weakly ionized helium plasma is investigated using an electrostatic probe. The existence of acoustic waves generated at the onset, or very early afterglow, is confirmed at neutral gas pressures as low as 0.1 Torr.

Multiple-mirror confinement of high-temperature plasma for fusion application is examined by numerical techniques using a fixed-scattering-center model. It is shown, in contrast to a linear relation found in an earlier study by Post, that the confinement time increases quadratically with the number of mirrors. We present the results of this scaling on the dimensions for a multiple-mirror reactor.

Transverse acoustic waves were generated electromagnetically at 9 GHz using In films with a conversion efficiency $\alpha$ of 5 × ${10}^{-5\mathrm{}}$. A good agreement is found between theory and experiment and we obtain the value of 620 Å for the superconducting penetration depth $\lambda$ at $0.4T_c$ and 5×${10}^{10}$ ${\mathrm{\Omega }}^{-1\mathrm{}}$ ${\mathrm{cm}}^{-2\mathrm{}}$ for the ratio of the conductivity to the mean free path for In. From the temperature dependence of $\alpha$ below the superconducting transition temperature it is concluded that pair scattering at the surface does not conserve momentum.

An experimental study has been made of the Riedel singularity in Sn—Sn-Oxide—Sn Josephson tunnel junctions. The data indicate that gap anisotropy rather than quasiparticle damping is the dominant factor in rounding off the observed singularity. However, it appears feasible to use the singularity as a probe of quasiparticle damping effects.

A new experimental configuration has been discovered in which motion of the superconducting domain structure can be realized under ideal conditions. The measured spatial periodicity of the moving structure in tin corresponds closely to the predictions of the Landau model.

We report here measurements of the excess fluctuation conductivity in one-dimensional Al samples. Because sample diameters were so small (typically, square cross sections ∼ 600 Å × 600 Å), we were able to measure excess conductivity over a temperature range much wider than previously possible. Good agreement with the Thompson-Maki theory is observed at temperatures $T<\mathrm{}1.3\mathrm{}{T}_c$. The recent theory due to Patton is also in qualitative agreement. Above $1.4T_c$ the data do not agree quantitatively with any theory.

Absolute measurements in the far infrared on superconducting Pb and Pb-In alloys show an enhanced surface resistance at the phonon frequencies, which is mainly due to the Holstein process. These results fit a new sum rule for the surface resistance and reveal an inherent and quantitative connection between the Holstein process and superconductivity.

Using a discretely tunable CO laser, we have studied the resonance enhancement of spontaneous spin-flip Raman scattering together with its polarization selection rules. Good agreement is found between experiment and theory.

We propose a theory of spin-phonon interactions in paramagnetic materials. The theory is based upon the conservation of total, i.e., spin plus lattice, angular momentum. Rotational invariance of the Hamiltonian of the coupled system leads to new contributions to the spin-phonon interaction. These new contributions are determined by the anisotropy of the crystal field acting on the spin system.

The electric-field-induced change in the linear dielectric function for the $E_1$ and $E_1+{\Delta }_1$ transitions of Ge, determined from low-field electroreflectance measurements, is shown to be in quantitative agreement with the third derivative of the linear dielectric function measured by high-resolution ellipsometry techniques. This result relates electroreflectance spectra to other types of modulation spectra and provides the first direct verification of the nonlinear optical interpretation of electroreflectance.

The potential produced by isoelectronic impurities is investigated and shown to be critically dependent upon screening. Two methods of calculation of the screened potential are used in this paper, one based on a first-principles wave-function approach and the other using the semiempirical theory of energy bands in semiconductors. The relaxation of the host crystal is also taken into account and shown to be important. The results are in satisfactory agreement with experiment.

Calculations and experimental results are presented on the nonlinear part of the interaction of free electrons with acoustic phonons which gives rise to acoustic sum-frequency generation. For a degenerate electron gas, the nonlinearity increases discontinuously at $\left|{\overrightarrow{\mathrm{q}}}_3\right|=2\mathrm{}{k}_{\mathrm{F}}$, where ${\overrightarrow{\mathrm{q}}}_3$ is the acoustic wave vector at the sum frequency and $k_{\mathrm{F}}$ is the electron Fermi wave vector. This abrupt increase was observed in GaAs using x-ray scattering.

The temperature dependence of the hyperfine field at Fe atoms was determined by Mössbauer and continuous-wave NMR methods for Fe-based alloys containing Ti, V, Cr, Mn, Co, and Ni impurities. A marked anomaly was found in the case of Mn, and a lesser one for Ni. The temperature anomaly of the hyperfine field at iron atoms in the neighborhood of Mn impurities can be described with a linear combination of two terms, one proportional to ${\mu }_{\mathrm{Fe}}$, the other to ${\mu }_{\mathrm{Mn}}-{\mu }_{\mathrm{Fe}}$. We suggest that the latter is brought about by the conduction-electron polarization.

Under the assumptions of the impulse approximation, there is a relation between the cross section for removing a particle from a system and the total binding energy of the system, if it is bound by two-body forces. This relation is established and applied to the ($p,2p$) reaction on nuclear targets. Data from recent experiments are used to obtain values for the total binding energy of the protons in various nuclei, which are then compared with the measured values.

Measurements of the small-angle elastic scattering of 4.8-$\frac{\mathrm{GeV}}{c}$ neutrons from hydrogen and heavier nuclei are reported over the range of four-momentum transfer between 0.002 and 0.05 ${\left(\frac{\mathrm{GeV}}{c}\right)}^2$. The data were used to determine the slope of the small-$\mathrm{}\left|t\right|\mathrm{}$ diffraction peak. The incident neutron beam covered a broad energy spectrum, and the detector included an ionization calorimeter to provide a measurement of the neutron energy.