We propose to use optical pumping with a high-power dye laser to produce the polarized Li atoms necessary for a polarized Li ion source. It should be possible to produce very intense beams of highly polarized Li ions.

A systematic comparison of the ($e$,$e^{\prime }$) and ($p$,$p^{\prime }$) transiton strengths for the excitation of unnatural-parity states of "stretched" configurations gives definite information on the high-momentum components of the tensor part of the nucleon-nucleon force. The available data emphasize the isovector part of the tensor force.

Precision hyperfine-structure measurements in the $4s4p{}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{}$ metastable state of ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ca}$ were performed using the atomic-beam magnetic-resonance method combined with a single-mode dye laser for the detection. For the first time the electric quadrupole moment of the particularly interesting ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ca}$ nucleus was accurately determined: $Q\left({}_{}{}^{43}{}_{}{}^{}\mathrm{Ca}\right)=-0.065\mathrm{}\left(20\right)\mathrm{}$ b. In addition, isotope shifts and hyperfine structure in the transition $4s4p{}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{}\leftrightarrow 4s5s{}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}$ were obtained using high-resolution laser spectroscopy.

Solutions of the Navier-Stokes equations for strong shock waves in a dense fluid agree well with recent atomistic simulations using nonequilibrium molecular dynamics.

Exact stability criteria for finite-amplitude solitons are derived. In contrast to previous investigations, deviations from quasineutrality and nonlinear plasma response are allowed for. Physical implications of the criteria are discussed.

${\mathrm{H}}^{-}$ and ${\mathrm{D}}^{-}$ densities are measured in low-pressure plasmas by photodetachment to confirm and extend previous work done with probes. Measurements indicate no isotope dependence, with $n_{-}$ rising in proportion to ${n_e}^3$ in the density range below $n_e={10}^{10}$ ${\mathrm{cm}}^{-3\mathrm{}}$. This functional dependence is consistent with ${\mathrm{H}}^{-}$ production by a nonlinear process such as dissociative attachment to excited hydrogen molecules and ${\mathrm{H}}^{-}$ loss by diffusion.

The free-volume distribution in a simulated Lennard-Jones liquid is heterogeneous. Chains of holes, appearing as segments rather than a continuous network, have lifetimes that are brief compared with the mean vibration period of the atoms. Larger isolated holes persist for longer times. If the chains are interpreted as dislocation cores, the observed dislocation density is 1.0×${10}^{14}$ ${\mathrm{cm}}^{-2\mathrm{}}$, but the actual density is probably higher.

In angle-resolved x-ray photoemission from the C $1s$ level of CO adsorbed on Ni(001), a peak in intensity with magnitude $\frac{I_{max}}{I_{\mathrm{back}}}\approx 1.5$ and full width at half maximum ≈ 25° is found to point along the surface normal. Single-scattering calculations for both a single CO molecule and a finite cluster verify that this peak is due to intramolecular scattering by O. The average orientation of CO is thus determined to be within 12° of normal, with an undetermined rms vibrational notion of ≲ 35°.

Computer experiments provide evidence that an intermolecular quadrupolar interaction on some crystal lattices can lead to short-range rotational "freezing" whose characteristics are similar to those of spin-glass ordering. Local order parameter and susceptibility are calculated as a function of temperature for a simple-cubic lattice, and the effects of dilution on the low-temperature limit of the order parameter are also discussed.

Two structural phase transition in K${\mathrm{C}}_{24}$ have been observed by x-ray diffraction: an order-disorder transition at $T_U=126.0\mathrm{}\pm 0.5$ K and a structural transition $T_L$ at about 93 K. Details of these transitions are presented, as well as the stacking sequences of the intermediate and low-temperature phases.

We present evidence for the existence of phase separation in gelatin gels having methanol-water mixtures as the gel fluid. The curves for the liquid-gel transition and the spinodal line were determined using measurements of viscosity and of scattered or transmitted light intensity, respectively. For the 30%-methanol-water mixture, the gelation curve terminates at the critical point. We also analyze the observed phase equilibria of the gels with a simple mean-field theory.

Optical free-induction dephasing times as long as 16 μsec, corresponding to an optical homogenous linewidth of 10 kHz, have been observed for the ${}_{}{}^3{}_{}{}^{}H_4^{}{}_{}{}^{}\leftrightarrow {}_{}{}^1{}_{}{}^{}D_2^{}{}_{}{}^{}$ transition of ${\mathrm{Pr}}^{3+}$ ions in La${\mathrm{F}}_3$ at 2°K. Measurements are facilitated by a frequency-locked cw dye laser and a new form of laser frequency switching. Zeeman studies reveal a Pr-F dipole-dipole dephasing mechanism where the Pr nuclear moment is enhanced in both ${}_{}{}^1{}_{}{}^{}D_2^{}{}_{}{}^{}$ and ${}_{}{}^3{}_{}{}^{}H_4^{}{}_{}{}^{}$.

The ferromagnetically coupled classical Heisenberg chain in an applied magnetic field has been studied by computer simulation. The results indicate the presence of a second collective mode, in addition to the damped spin-wave-like modes which have previously been observed in the absence of a magnetic field. For intermediate wavelengths, the mode manifests itself by well-defined oscillations in the energy-density correlation function, and by a second peak in the spectrum of the longitudinal spin-density correlation functions.

We have measured the photomission intensity versus photon energy curves of the Sn $4d_{\frac{5}{2}}$ level in SnS and Sn${\mathrm{S}}_2$ and the In $4d_{\frac{5}{2}}$ and Se $3d$ levels in InSe up to 110 eV above threshold. The structure observed in these curves is mostly due to nearest-neighbor backscattering. This raises the possibility of surface extended x-ray-absorption fine-structure experiments by photomission intensity measurements.

A quantitative derivation is presented for the production of the acoustic signal in a photoacoustic cell, taking into account the finite surface thermal resistance of the solid.

Analysis of the high-temperature series expansions of a continuous-spin Ising model (i.e., a lattice $\lambda :{{\varphi }^4:}_d$ field theory) indicates that the strong-coupling limit of $\lambda :{{\varphi }^4:}_3$ is distinct from the critical-point theory of the continuous-spin Ising model for sufficiently Ising-like spin distributions. In four dimensions we find that the $\lambda :{\varphi }^4:$ field theory is trivial.

We relate two popular methods of renormalization; minimal subtraction and momentum-space subtraction. It is shown that $\frac{{\Lambda }_{\mathrm{mom}}}{{\Lambda }_{min}}=5.73\mathrm{}$, where $\Lambda$ is the mass used to parametrize the quantum-chromodynamic running coupling constant. Perturbation expansions are compared in the two methods. Our results support the conjecture that momentum-space subtraction leads to better convergence and that, therefore, ${\Lambda }_{\mathrm{mom}}$ is the parameter which should be measured by experiments.

This paper presents results of a beam-dump experiment performed at the Brookhaven alternating-gradient synchrotron to search for prompt sources of neutrinos and axionlike particles. We observe no excess of ${\nu }_e$ or ${\overline{\nu }}_{\mu }$ events, and no excess in neutral-current events over that expected from neutrinos from $\pi$ and $K$ decays. We report on limits of prompt particle-production cross sections and lifetimes.

Particle decay modes of the giant quadrupole resonance in ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ have been determined in a particle-particle angular correlation experiment. The branching ratios are (59±12)% and (12±4)% [(30±6)% and (6±2)% of the isoscalar $E2\mathrm{}$ energy-weighted sum-rule strength] for proton and $\alpha$-particle decay, respectively, and are very similar to those of the underlying continuum and the statistical-model predictions. Our results disagree with a recent electroproduction singles experiment.

Elastic electron scattering has been used to determine the transverse form factor of the ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$ ground state in the effective momentum-transfer range $0.55<~q_{\epsilon }<~2.8$ ${\mathrm{fm}}^{-1\mathrm{}}$. The data show considerable deviation from single-particle predictions; in particular, a sizable suppression of the $M3\mathrm{}$ and an enhancement of the high-$q$ side of the $M5\mathrm{}$. Recent shell-model, core-polarization, and meson-exchange calculations are not adequate to explain these effects.