A long-range imaginary optical potential approximating the effects of quadrupole Coulomb excitation is derived in closed form. An analytical closed form for sub-Coulomb elastic scattering is obtained by inserting this potential into a weak-absorption model.

Transient magnetic fields for ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$ and ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ recoiling into cobalt and iron have been deduced from IMPAC (ion-implantation perturbed angular correlation) measurements. The transient field in cobalt is substantially larger than that in iron in contrast to the field on ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$, which is stronger in iron. This can be explained by molecular-orbital promotion in the ion-atom collisions, which governs the $K$-shell polarization of light ions.

We report the results of small-angle ruby-laser Thomson-scattering measurements of the parametric excitation of plasma waves by C${\mathrm{O}}_2$-laser radiation at quarter-critical density in a laser-heated gas-target plasma. From supplementary data obtained from interferometry and large-angle ruby-laser scattering we infer that the threshold conditions for a convective decay are satisfied.

Hard gluon bremsstrahlung in $\mu p$ scattering produces final-state hadrons with a large component of momentum transverse to the virtual-photon direction. Quantum chromodynamics can be used to predict not only the absolute value of the transverse momentum, but also its angular distribution relative to the muon scattering plane. The angular correlations should be insensitive to nonperturbative effects.

Laser-light absorption and radiation forces are investigated for weakly collisional ($\frac{\nu }{\omega }\ll 1$), rigid, two-step plasma profiles in planar and spherical geometry. For the first step near critical density, the second step above critical, and appropriate step lengths, we find strong absorption even for weakly collisional plasmas. We show, however, that the radiation forces may not permit such profiles to persist in realistic, dynamic situations.

Measurements of energetic-ion energy distributions produced from C${\mathrm{D}}_2$ and C${\mathrm{H}}_2$ targets are compared with a numerical model. The model describes the ambipolar expansion of hot electrons and two relatively cold ion species from an electron pressure gradient. For C${\mathrm{D}}_2$ the plasma expansion is adequately represented by a single ion species, whereas for C${\mathrm{H}}_2$ two-ion fluids are required to account for the energy and the relative behavior of the high-energy ion species.

Formulas for the electron thermal conductivity have been derived in the collisional and collisionless limits for the case of destroyed magnetic surfaces.

We examine in computer simulation and theory some important properties of the distributions of electrons heated by resonance absorption of intense laser light. Comparison is made with recent experiments.

The dependences of photoionization cross section on incident photon energy and electron emission on polar exit angle are used to determine the location of chemisorption sites. Calculations are made for the $c(2\mathrm{}\times 2)$ S-Ni(001) and CO-Ni(001) systems. Comparing with experiment, it is found that angle-resolved ultraviolet photoelectron spectroscopy data are very sensitive to the coordination number of the adsorption site and less sensitive to the overlayer-substrate interlayer spacing.

A variational version of the cellular method is developed to calculate the electronic structure of molecules and crystals. Because of the simplicity of the secular equation, the method is easily implemented. Preliminary calculations on the hydrogen molecular ion suggest that it is also accurate and of fast convergence.

We find that a submonolayer of magnetic impurities placed 10-100 Å into the metal electrode of a metal-insulator-metal tunnel junction condensed on a liquid-helium-cooled substrate, produces narrow peaks about zero bias in the dynamic tunneling resistance from which, in accord with the theory of Mezei and Zawadowski, the energy dependence of the scattering amplitude in the Kondo effect and the momentum dependence of the $s-d$ exchange integral may be deduced.

The first observation of an electron-hole liquid (EHL) in the polar semiconductor cubic SiC is reported. The temperature and excitation dependence of the luminescence, time-delayed spectra and decay times (${\tau }_{\mathrm{EHL}}=57\mathrm{}\pm 3$ nsec) have been measured. An EHL binding energy of 19.5±4 meV, a high critical temperature of ∼41 K, and a low-temperature density of 7.8×${10}^{18}$ ${\mathrm{cm}}^{-3\mathrm{}}$ are deduced and demonstrate the strong influence of electron-phonon coupling and reduced screening for EHL binding.

The cross sections for the line-reversed reaction pairs $K^{+}n\to K^{0}p$ and $K^{-}p\to {\overline{K}}^{0}n$, and $K^{+}p\to K^0{\Delta }^{++}$ and $K^{-}n\to {\overline{K}}^0{\Delta }^{-}$ have been determined with high statistics and good relative normalization at 8.36 and 12.8 GeV/c in a spectrometer experiment at Stanford Linear Accelerator Center. The cross sections for the $K^{+}$-induced reactions are larger than for the $K^{-}$, contrary to the expectations of weakly-exchange-degenerate Regge-pole models. The ratio of the reaction cross sections is about the same as at lower energies and shows little change with momentum transfer.

A type of angle-dependent uv photoemission measurement has been used to study variations in the intermolecular polarization effect at the surface of thin condensed anthracene films. The top molecular layer exhibits a 1.2-eV relaxation energy in response to the polarization of the hole state created in photoemission event. The second and subsequent layers exhibit a different value of about 1.5 eV. This result corresponds to the observation of a surface electronic molecular-ion state on a molecular solid.

Phonon generation by GaAs epilayers and $p-n$ junctions is studied by means of a superconducting bolometer and time-of-flight techniques. The polarization of the emitted radiation is found to be sensitive to doping in agreement with theoretical selection rules. The relative strength of the radiative and nonradiative processes is shown to depend on defect density and bias and demonstrates the energy transfer processes in $p-n$ junctions.

We report the first observation of the spin polarization of sodium atoms by laser optical pumping in hydrocarbon flames at atmospheric pressure. The spin relaxation times in different parts of a flame are measured, and they vary from 0.5 μsec to shorter than 40 nsec. We have also observed rf magnetic resonance transitions in an optically pumped flame. Our observations may be useful as a new flame diagnostic tool or for rf spectroscopy of free radicals and ions in a flame.

The method of synchronizing clocks in accelerating frames through the use of electromagnetic signals can be tested experimentally by considering clocks placed in a set of synchronous satellites about Earth's equator. In synchronizing the clocks in a circuit about the equator, a large measurable time difference (9 μsec) is obtained between the two clocks in the same satellite from which the synchronization process is started and completed. Similarly, Earth's rotation may cause discrepancies in terrestrial time keeping.

We show that a relativistic, one-pion-exchange, three-body theory including the (3,3) isobar and full spin dependence adequately describes the inelastic nucleon-nucleon cross section at energies where only single-pion production is important. Unitarization of the amplitude plays a significant role in obtaining the correct energy dependence. To fit elastic cross sections, however, will require inclusion of short-range potentials.

We have studied the coherent dissociation of neutrons into $p{\pi }^{-}$ systems, for a variety of nuclear targets, at incident momenta up to 300 GeV/c. Using a model incorporating both electromagnetic and hadronic production, we have extracted total cross sections for scattering of unstable $p{\pi }^{-}$ systems on nucleons.

Based on four ${\mu }^{+}{e}^{-}X$ and six ${\mu }^{-}{e}^{+}X$ events (with estimated backgrounds 1.1 and 0.6 events, respectively), in the Fermilab 15-in. neon (64 at.%) hydrogen bubble chamber, the fractions of ${\mu }^{+}{e}^{-}$ and ${\mu }^{-}{e}^{+}$ production relative to ${\overline{\nu }}_{\mu }$ and ${\nu }_{\mu }$ charged-current interactions in a broad band $\stackrel{\left(¯\right)}{\nu }$ beam are, respectively, $\overline{f}=\left({0.15}_{-0.08\mathrm{}}^{+0.14\mathrm{}}\right)\%$ and $f=\left({0.34}_{-0.13\mathrm{}}^{+0.23\mathrm{}}\right)\%$; $\frac{\overline{f}}{f}={0.45}_{-0.3\mathrm{}}^{+0.6\mathrm{}}$.