The two lines resulting from the multielectron transitions $1s^{-2\mathrm{}}\to 2s^{-1\mathrm{}}2{p_{\frac{1}{2}}}^{-1\mathrm{}}$ and $1s^{-2\mathrm{}}\to 2s^{-1\mathrm{}}2{p_{\frac{3}{2}}}^{-1\mathrm{}}$ were resolved for both Fe and Co. Their energies were determined and their relative intensities were measured and compared with the intensities of the $K\alpha$ hypersatellites of the elements.

The first experimental observation of ablation-pressure distribution on spherical targets was made at several focusing conditions by flash x-ray radiography. The results indicate that lateral smoothing of the ablation pressure is dominated by the magnetic field generation due to hot-electron streams and/or local-heating-induced $\nabla n\times \nabla T$ at an intensity near ${10}^{15}$ W/${\mathrm{cm}}^2$ from a 1.053-μm laser.

Nuclear fusion rates can be enhanced or suppressed by polarization of the reacting nuclei. In a magnetic fusion reactor, the depolarization time is estimated to be longer than the reaction time.

The charge state of a projectile ion traveling through a plasma target under conditions relevant to ion-beam fusion is calculated. It is found that, at the projectile energies and target parameters considered, the projectile ionization is significantly higher than that of the same projectile species in a cold target. The resulting strong effects on the range and on the shape of the energy deposition profile are shown in several examples of full dynamic calculations.

Order-of-magnitude improvements in the level and duration of current driven by lower-hybrid waves have been achieved in the PLT tokamak. Steady currents up to 165 kA have been maintained for 3.5 sec and 420 kA for 0.3 sec by 800-MHz rf power alone. The principal current carrier appears to be a high-energy (∼ 100-keV) electron tail, concentrated in the central 20- to 40-cm core of the 80-cm-diam discharge column.

A satellite peak has been observed in the NMR spectrum of rotating ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-$A$; the peak intensity depends linearly on $\Omega$ at the high angular velocities, $\Omega =0.6-1.5\mathrm{}$ rad/s, needed to resolve it. The frequency shift of the satellite is independent of $\Omega$. These results strongly suggest the existence of vortices in rotating ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-$A$ with the vortex density proportional to $\Omega$. Another satellite peak also has been observed which probably is due to solitons.

A Monte Carlo study has been made of metastable states in the three-dimensional Glauber-kinetic-Ising model with Iong-range interaction. It is found that the properties of pseudospinodals converge rapidly with increasing interaction range to those predicted for the mean-field spinodal. A breakdown of the classical droplet model in the vicinity of this spinodal was also observed.

Photon-stimulated desorption of ${\mathrm{O}}^{+}$ ions has been obtained from ${\mathrm{Na}}_x\mathrm{W}{\mathrm{O}}_3$ in the range $30 \mathrm{eV}<h\nu <84\mathrm{} \mathrm{eV}$. The results show applicability of the Knotek-Feibelman interatomic Auger decay model for ion desorption and show the first observation of bonding-site selectivity in the process. The local coordination of the desorption site and the nature of the bonding which contributes to ion desorption are also discussed.

Homogeneous nucleation of phase separation has been investigated in liquid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ mixtures. Near the tricritical point the maximum supercooling marking the boundary of the metastable region is strongly enhanced compared to ordinary critical fluids. Beyond the metastability limit, the observed growth of the new phase is in good accord with a theory of Lifshitz and Slyozov.

The dynamic structure factor and its generalization for transverse excitations for the normal modes of a Lennard-Jones glass are calculated. The results are compared with those for a polycrystal. The longitudinal dispersion curve shows a remarkably deep minimum at the wave vector where the structure factor has a peak.

Time-differential and stroboscopic measurements of the perturbed angular $\gamma$-ray distribution for isolated ${}_{}{}^{88}{}_{}{}^{}\mathrm{Y}$ ions in liquid Sr and Rb are reported. A drastic drop in the Knight shift and the nuclear relaxation rate is observed as the Sr matrix is replaced by Rb. This implies an almost vanishing density of $5s$ states on the Y ion in Rb at the Fermi level. A volume expansion of the Y Wigner-Seitz cell is suggested as the mechanism causing this anomalous behavior in $\mathrm{Rb}$ Y.

The thermodynamic properties of an easy-plane ferromagnetic chain have been shown to differ from those of the sine-Gordon theory. This difference is accounted for in terms of an instability of the sine-Gordon solitons. The calcualted renormalized soliton energy is in agreement with the experiments.

The observation is reported of a remarkable persistence of the $1s$ exciton resonance in transient picosecond absorption spectra of GaAs under conditions of resonant optical excitation up to pair densities two orders of magnitude above the Mott density. The stability (excess linewidth < 0.8 meV at $n=6\mathrm{}\times {10}^{16}$ ${\mathrm{cm}}^{-3\mathrm{}}$) of this dense exciton gas against decay into the energetically more favorable continuum of electron-hole pairs is due to the relatively weak self-screening of discrete excitons.

The pulsed-laser piezoelectric-transducer optoacoustic spectroscopy is used to study phonons in hexagonal-phase solid normal hydrogen. At temperatures of ∼ 11 K, the phonon excitations associated with double-molecular transitions are predominantly transverse-optical phonons, whereas the excitations associated with single-molecular transitions are predominantly longitudinal-optical phonons. The LO phonon density of states is obtained for the first time.

A phase transition was observed in the nuclear spin system of metallic copper in external fields less than 0.22 ± 0.02 mT and at entropies in the range of $\mathrm{}(0.4-0.6)R\ln 4$; the transition temperature was estimated to be of the order of 100 nK. Indications of a second anomaly at 0.08 ± 0.01 mT were also seen. The transition is antiferromagnetic and of first order. It is accompanied with large overcooling of the paramagnetic phase, which explains the discrepancies in the previous results.

Baxter has solved a restricted class of square lattice gas models with nearest-neighbor exclusion (thus "hard squares") and next-nearest-neighbor interactions. Arguments are presented which demonstrate that the subspace spanned by his exact solution contains the line of tricritical points and the associated surface of first-order transitions of hard squares with attractive next-nearest-neighbor interactions. The tricritical exponents so identified confirm those obtained by Nienhuis for a dilute Ising model.

Skyrme has shown that the SU ⊗ SU(2) chiral model has nontrivial topological sectors with static solutions for suitable Lagrangians. The baryon number $B$ and strangeness of these sectors have been studied, and the existence of bound states of the nucleon field to the lightest solitons is shown. It is found that there must be long-lived levels with $\mathrm{}\left|B\right|\mathrm{}\gtrsim 6$ and $\mathrm{}\left|s\right|\mathrm{}\gtrsim 6$ and $1.8 \mathrm{GeV}\lesssim m\lesssim 5.6 \mathrm{GeV}$, some having half-integral charge and exotic relation between $B$ and $s$, that can be pair produced in, say, $e^{+}{e}^{-}$ collisions.

Single-$\Lambda$ production with no other strange particles in the final state is observed in charged-current neutrino interactions in the deuterium filled 15-ft bubble chamber at Fermilab. This phenomenon is interpreted as a signal for inclusive production of charmed baryons followed by ${{\Lambda }_c}^{+}\to \Lambda +X$ decays. The product of total ${{\Lambda }_c}^{+}$ cross section by branching ratio for this process is found to be (2.0±0.74±0.65)% of the total charged-current neutrino cross section.

Published ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$-${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ elastic scattering data at 161.1, 288.6, and 1030 MeV have been analyzed. All three angular distributions show evidence for a nuclear rainbow whose energy evolution agrees with semiclassical predictions. Other features of "light-ion" scattering are confirmed by the optical-model analysis. It is concluded that the appearance of a nuclear rainbow is not determined by the mass of the projectile.

Precise measurements are reported of the spin-correlation parameter $A_{\mathrm{NN}}$ for 500-800 MeV $\mathrm{pp}$ elastic scattering at ${\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}=\frac{\pi }{2}$. While not reproducing the large value of $A_{\mathrm{NN}}$ reported earlier at 697 MeV, the data show a pronounced maximum in the 90° triplet-to-singlet ratio near the location of the reported ${}_{}{}^3{}_{}{}^{}F_3^{}{}_{}{}^{}$ dibaryon resonance. In contradiction with an earlier report, structure is not found in the moduli of the singlet and triplet amplitudes.