Analysis of published spectral data shows that the photons relevant to photodissolution of metals in amorphous chalcogenide semiconductors are absorbed in the metal and not in the semiconductor. It is argued that light does not enhance the diffusion of metal atoms in the chalcogenide matrix, but triggers a solid-state chemical reaction at the metal-semiconductor interface. A new amorphous phase in the Ag-As-S system, ${\mathrm{As}}_4$${\mathrm{Ag}}_5$${\mathrm{S}}_6$, is postulated to explain the peculiar physical and chemical properties of the new photogenerated material.

Samarium clusters exhibit mixed-valence behavior which is sensitive to particle size. X-ray photoemission and ultraviolet photoelectron spectroscopy data show samarium to be primarily divalent ($4f^6$) at small particle size. The trivalent state ($4f^5$) becomes progressively more abundant with increasing size, becoming the dominant state for the bulk metal. These results are interpreted in terms of band narrowing due to reduced surface coordination, which is more dominant than surface tension effects in establishing the valence of small samarium clusters.

The bandlike $\mathrm{XVV}$ Auger transitions of glass-forming elements are shown to provide a sensitive method for investigating the electronic properties of metallic glasses. For amorphous ${\mathrm{Fe}}_{82}{\mathrm{B}}_{18-x}{\mathrm{Be}}_x$, not only do the Auger results correlate remarkably well with the magnetic data, but more importantly, a 14-eV shift was detected in the Be $\mathrm{KVV}$ Auger spectra between $x=4\mathrm{}$ and $x=5\mathrm{}$. This large shift reflects a pronounced change in the short-range order of this metallic glass system.

The two-impurity Kondo problem is studied by use of perturbative scaling techniques. The physics is determined by the interplay between the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between the two impurity spins and the Kondo effect. In particular, for a strong ferromagnetic RKKY interaction the susceptibility exhibits three structures as the temperature is lowered, corresponding to the ferromagnetic locking together of the two impurity spins followed by a two-stage freezing out of their local moments by the conduction electrons due to the Kondo effect.

We report the temperature-dependent x-ray diffuse scattering of ${\left(\mathrm{NMP}\right)}_x{\left(\mathrm{Phen}\right)}_{1-x}$-(TCNQ) as a function of conduction-electron density ($x$). With decreasing $x$ three different unique electronic instability regimes are successively observed on the TCNQ chains: (i) the $2k_{\mathrm{F}}$ instability for $\frac{2}{3}<~x<~1$, (ii) both $2k_{\mathrm{F}}$ and $4k_{\mathrm{F}}$ instabilities for $0.57<~x<~\frac{2}{3}$, and (iii) the $4k_{\mathrm{F}}$ instability alone for $x$ close to 0.5. These results provide direct evidence for the critical role of interchain screening in determining the magnitude of the effective Coulomb interaction.

Measurements of the spectrum of the night sky have been made in the wave-number region 5 to 35 ${\mathrm{cm}}^{-1\mathrm{}}$ with use of a liquid-helium-cooled rocket-borne interferometer. The observed spectrum deviates from a 2.7-K Planck spectrum, there being a deficit of energy between 5 and 11 ${\mathrm{cm}}^{-1\mathrm{}}$ and an excess at higher wave numbers.

We propose the condensation of dynamical monopoles and their strings as the mechanism responsible for the rapid crossover from weak to strong coupling in SU(2) lattice gauge theory. By adding to the Wilson action a chemical potential for monopole formation, we are able to study the crossover in an extended phase plane. We find a critical value for the potential, related to the transition in a dual Ising model, above which monopoles are absent. Support for this picture is garnered from Monte Carlo simulations.

't Hooft—Polyakov monopoles are shown to admit spin in the sense of Finkelstein.

Cross sections for elastic scattering of neutrons from ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ have been measured at 30.3 and 40.0 MeV and analyzed to obtain optical-model potentials. The optical potentials for neutron and proton scattering are found to be very similar after a correction for Coulomb effects, indicating that a static charge-symmetry-breaking Hartree potential is too small to explain the Coulomb-energy anomaly for bound states.

Recent studies of the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$,$\alpha$)${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ at $E\left({}_{}{}^{16}{}_{}{}^{}\mathrm{O}\right)=145\mathrm{}$ MeV have revealed the existence of several broad states with $E_x\left({}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}\right)=20\mathrm{} \mathrm{to} 60$ MeV, which have been interpreted as members of the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ molecular band $J^{\pi }=\left({10}^{+}\right)$ through $J^{\pi }=\left({18}^{+}\right)$. Subsequent investigation, however, has failed to reveal the expected partial width for ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$*→${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$+${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$. We show that these states can be interpreted as an extension of the ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ yrast sequence which is populated by the well understood high-spin selectivity of $\alpha$-particle evaporation from a ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ compound nucleus.

We have measured the inelastic scattering of 35-MeV protons from ${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}$ and from ${}_{}{}^{234,236,238}{}_{}{}^{}\mathrm{U}$. Angular distributions were extracted for $J^{\pi }=0^{+}-8^{+}$ members of the ground-state rotational bands, and were analyzed with use of coupled-channels calculations for scattering from a deformed optical potential. The deformation parameter ${\beta }_6$ is positive for ${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}$ and ${}_{}{}^{234}{}_{}{}^{}\mathrm{U}$, nearly zero for ${}_{}{}^{236}{}_{}{}^{}\mathrm{U}$, and negative for ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$. The trends of the deformation parameters and multipole moments are explained qualitatively by a simple model.

Light-particle emission in the fusion reactions in the system ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$+${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ at 100 MeV has been studied with use of coincident techniques. Comparison of the data with a statistical model accounts for the energy and angular distributions of the products, the particle multiplicities, and the dealignment in the evaporation cascade. However, (18±5)% of the evaporation residue cross section is of nonequilibrium origin and is interpreted in the framework of preequilibrium emission from complex configurations.

The magnetic circular dichroism of excimer absorption bands is used to obtain the first direct information about the angular momentum and angular momentum coupling schemes of excimer molecules.

The banana orbits of high-energy trapped particles in tokamaks are found to diffuse rapidly in the radial direction if the toroidal ripple exceeds a low critical value. During this diffusion the energy, the magnetic moment, and the value of the magnetic field strength at the banana tips are conserved.

Observations of radiation from iron and from argon used as a test gas indicate that co-injection inhibits impurity accumulation in the interior of ISX-$B$ (impurity study experiment) tokamak discharges, but counter-injection enhances accumulation. These results agree qualitatively with recent theoretical calculations.

Laser-driven thermal-electron-transport inhibition is studied with use of a self-consistent Monte Carlo model for all the electrons. Comparison is made with the results of flux-limited single-group-diffusion calculations. The need for severe flux limiters is traced to deficiencies in the classical diffusion modeling that can excessively heat the overdense surface matter of a pellet, ignore coronal decoupling of the thermals electrons, and neglect the effects of electric-fields for a return current through density gradients.

The first stage of epitaxial growth of Au on Ag(111) has been studied by MeV ion scattering. The monolayer-by-monolayer (Frank-van der Merwe) growth mode for this system is confirmed by measurements of (1) the Ag surface peak, (2) the Au-Au shadowing effect, and (3) the Ag Auger intensity.

Combining heat-pulse scanning and tunnel-junction detection, we have observed ballistic propagation of high frequency (>700 GHz) acoustic phonons over ∼1-mm path lengths in germanium. The ballistic nature of the phonons is determined by sharp variations in phonon flux with propagation angle. The phonon focusing pattern is significantly altered from that obtained with an Al bolometer (which is sensitive to longer-wave-length phonons) revealing a modification of the phonon slowness surface due to dispersion.

A study of the phase diagram near the nematic-smectic-$A$-smectic-$C$ multicritical point and of nematic-smectic-$C$ transition entropies leads to the conclusion that this is not a Lifshitz point. It is shown that a biaxial second-rank tensor order parameter may be needed.

We report a high-resolution x-ray study of the fluctuations in a system exhibiting nematic, smectic-$A$, and smectic-$C$ phases, with emphasis on the NAC multicritical region. We find that the transverse mass density fluctuations are always Lorentzian in character in explicit disagreement with the Lifshitz model for this system. Unexpectedly, both the mass density fluctuations and the tilt order parameter exhibit isotropic heliumlike critical exponents near the NAC point.