The temperature dependence of the spontaneous polarization of ferroelectric triglycine sulfate has been determined in the range 2.2-20 K by measuring the charge released by a large crystalline sample with a Keithley electrometer. Above ∼8 K this temperature dependence is $\Delta P_s=C{e}^{-\frac{\Delta }{\mathrm{kT}}}$, corresponding to a two-level system with energy splitting $\Delta =h{\nu }_{\mathrm{E}}=9.08\mathrm{}\times {10}^{-15\mathrm{}}$ erg, while between 2.2 and 4 K it is $\Delta P_s=A{T}^{\frac{3}{2}}$. Both temperature dependences are consistent with recent specific-heat measurements by Lawless.

We demonstrate the feasibility of Auger-photoelectron coincidence spectroscopy (APECS) and use this technique to study the Cu $L_{23}{M}_{45}{M}_{45}$ Auger transitions. With APECS the Auger lines can be identified unambiguously and the Coster-Kronig-preceded Auger lines separated from the main $L_3{M}_{45}{M}_{45}$ lines. The background due to scattered electrons is strongly reduced relative to that in conventional Auger or photoelectron spectroscopy. Some other interesting experiments that can be done with this technique are discussed.

A beam of positrons is used to study positronium (Ps) formation at the surfaces of clean, single-crystal targets. The Ps formation probability changes with incident energy $E$ as ${(\frac{E}{E_0}+1)}^{-1\mathrm{}}$, with $E_0=915\mathrm{}\left(30\right), 6000\left(150\right), \mathrm{and} 2900\left(150\right)\mathrm{}$ eV for Si, Ge, and Al at 300 K. Since $E_0$ is observed to be temperature dependent, it is argued that Ps is not being formed by backscattering from the surface; rather, the energetic positrons thermalize in the bulk and diffuse to the surface where about half of the positrons escape as free Ps at 300 K.

Azimuthal anisotropies in core-level x-ray photoemission from $c(2\mathrm{}\times 2)\mathrm{O}$ on Cu(001) have been found to show a strong dependence on polar emission angle. The anisotropies observed are $\frac{\Delta I}{I_{max}}\lesssim 24\%$ for O 1s emission, and ≲ 41% for Cu $2p_{\frac{3}{2}}$ and Cu $3p$ emission. A single-scattering theoretical model is found to describe well both the O and Cu data, and suggests that O is present in fourfold coordination sites for which the O atoms are coplanar with the Cu surface atoms.

By choosing a suitable probability distribution the decay of an unstable state of a macroscopic system can be described deterministically; the effects of fluctuations then show up in the initial probability density. There is no need to distinguish an initial linear and diffusive regime from a later deterministic one.

We point out that the polarization $P$ of a scattered or produced quark is calculable perturbatively in quantum chromodynamics for $e^{+}{e}^{-}\to q\overline{q}$, large-$p_T$ hadron reactions, and large-$Q^2$ leptoproduction, and is infrared finite. The quantum-chromodynamics prediction is that $P=0\mathrm{}$ in the scaling limit. Experimental tests are or will soon be possible in $\mathrm{pp}\to \Lambda X$ [where presently $P\left(\Lambda \right)\simeq 25\%$ for $p_T>2\mathrm{}$ GeV/c] and in $e^{+}{e}^{-}\to \mathrm{quark}\mathrm{jets}$.

We carry out a new, generalized analysis of nuclear $\beta$ decay and semileptonic hyperon and $K_{e3\mathrm{}}$ decays. The results are used to determine two quark mixing angles in the sequential Weinberg-Salam model.

The local-energy approximation is used to replace the factorization approximation in distorted-wave theories of ($p, 2p$) reactions. Significant modifications seem suggested.

Cross sections have been measured for the production of ${}_{}{}^6{}_{}{}^{}\mathrm{He}$, ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, and ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ in the $\alpha +\alpha$ reaction between 61.5 and 158.2 MeV. The significance of these measurements for theories of lithium nucleosynthesis is discussed.

A zero-parameter, classical, many-body model of relativistic heavy-ion collisions is proposed. Inclusive proton cross sections from 250- and 400-MeV/nucleon ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$+U, 400-MeV/nucleon ${}_{}{}^4{}_{}{}^{}\mathrm{He}$+U, and 800-MeV/nucleon ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$+NaF collisions are in good agreement with the model.

Transverse ($E6\mathrm{}$) and longitudinal (C6) cross sections for the excitation of the $J^{\pi }=6^{+}$, $E_x=5.125\mathrm{}$ MeV state in ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ were measured by means of inelastic electron scattering. The deduced isoscalar component of the particle-hole wave function is found to be two orders of magnitude greater in amplitude than the isovector. This implies that the particle-hole isospin is relatively pure $\tau =0\mathrm{}$ and is not significantly mixed with $\tau =1\mathrm{}$.

We report the observation of spontaneous radiative emission during the collision of two excited Ba atoms. The emission occurs at the sum energy of the excited atoms and is the emission analog of the laser-induced inelastic collision process. We measure a collision cross section for deexcitation by spontaneous radiative emission of 2.6×${10}^{-20\mathrm{}}$ ${\mathrm{cm}}^2$.

The probability for production of $K$-shell x rays by protons elastically scattered from ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ is observed to change as one varies the proton energy over the $s_{\frac{1}{2}}$ nuclear resonance at $E_p=3.151\mathrm{}$ MeV. The results are interpreted theoretically in terms of interfering products of atomic ionization and energy-dependent nuclear scattering amplitudes.

A theoretical and simulation study shows that a plasma subject to a Rayleigh-Taylor instability exhibits spontaneous magnetic fields. Such magnetic fields in a laser-fusion configuration may significantly reduce the hot-electron thermal transport. Modification in the transport also suggests that the ablation velocity is altered.

Two-plasmon decay of 10.6-μm radiation has been studied in a long density scale length (∼300 μm) plasma using Thomson scattering and interferometry. Enhanced levels of both electron and ion plasma waves have been observed near $\frac{1}{4}{n}_c$ which are quenched during the C${\mathrm{O}}_2$-laser pulse. Profile modification localized at $\sim \frac{1}{4}{n}_c$ has also been observed.

We report the first results of a thermodynamic analysis of data for ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ adsorbed on Grafoil. The ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-graphite binding energy is in excellent agreement with a prediction made on the basis of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$-graphite atomic scattering data.

We have studied the lattice dynamics of bcc Zr at 1400 K. We find that (a) the [111] longitudinal branch plunges rapidly to low frequencies in the vicinity of $q=\frac{2}{3}\mathrm{}\left[111\right]\mathrm{}$ indicating a nautral inclination for this metal to undergo a structural transformation to the $\omega$ phase, (b) the [110] longitudinal branch is anomalous at the zone boundary, and (c) the condition of elastic isotropy is satisfied to within experimental error. Temperature-dependent elastic peaks were observed in the vicinity of the reciprocal lattice points of the $\omega$ phase.

The surface vibrational modes of atomic hydrogen adsorbed on W (100), observed by electron-energy-loss spectroscopy in off-specular directions, indicate bridge bonding at all coverages. The vibrational frequencies show a dependence on the W-H-W bond angle which changes due to reconstruction of the tungsten lattice. The results indicate a W (100) $c[2\mathrm{}\times 2]\mathrm{H}$ low-coverage ${\beta }_2$ phase consisting of atoms occupying bridge sites on a $(\sqrt{2}\times \sqrt{2})R45\mathrm{}°$ reconstructed substrate similar to the clean crystal surface at low temperatures.

The transmission of ballistic longitudinal (L) and transverse (T) phonon pulses from sapphire to liquid He II at temperatures of $T=0.25\mathrm{}$ K has been measured as a function of the pulse power and He II hydrostatic pressure for the first time. Under these experimental conditions, the converted L- and T-mode pulses propagate ballistically through He II. The results indicate that the transmission probability is different for the L and T modes and that the intensity ratio of converted L and T modes changes with the He II pressure.

Newtonian capillary shear flow was observed for the first time in a cholesteric liquid crystal with the helix axis perpendicular to the flow. The effective viscosity in the cholesteric phase had a magnitude comparable to the viscosity of the isotropic liquid extrapolated to the cholesteric temperature. Oscillatory pitch dependence of the viscosity was seen when the pitch length was comparable to the capillary width.