We present a synchrotron-x-ray study of the smectic-C (${\mathrm{S}}_{\mathrm{C}}$) and smectic-I (${\mathrm{S}}_{\mathrm{I}}$) phase in a single-domain freely suspended film. Weak bond-orientational order in the ${\mathrm{S}}_{\mathrm{C}}$ phase evolves continuously into the ${\mathrm{S}}_{\mathrm{I}}$ phase so that the two phases are not thermodynamically distinct. From a Fourier analysis we obtain the hexatic order parameter ${\mathrm{C}}_6$, the coefficient of cos6χ. The higher &, with ${\mathrm{\sigma }}_{\mathrm{n}}$≃n+0.3n(n-1), in agreement with a scaling theory.

A theory for the Helmholtz free-energy functional F of inhomogeneous simple liquids is presented in which hard-sphere perturbation theory is utilized to separate F into primarily entropic and internal-energy contributions. The entropy of the hard-sphere reference system is obtained from the weighted-density approximation and the internal energy is determined from an expansion about the uniform-liquid value. The thermodynamic functions of a model Lennard-Jones solid, liquid, and vapor are then calculated and the resulting ρ-T phase diagram is found to be in good agreement with all aspects of simulation studies, including the Lindemann parameter along the freezing curve.

When diatomic nuclear motion is described in an adiabatic approximation by a guage field, the conserved angular momentum possesses a nonkinematical contribution. The present work derives this expression and, by a change of basis, gives a simple form for the addition.

We present evidence for inclusive F-meson production in B-meson decay. The product branching fraction B(B→FX)B($F^{+}$→φ${\pi }^{+}$) is measured to be 0.0038±0.010. The F momentum spectrum indicates the presence of a large component of two-body final states in the decay B→FX.

The possible effects of different off-shell extrapolations of πN scattering are investigated for NN scattering based on the relativistic unitary three-body model. The conventional Δ-isobar model with a soft form factor is found not to lead to a successful description of the pion-production cross section. A refined model which includes the background interactions enables us to use harder form factors, bringing about marked improvements in reproducing the data.

A model-independent multipole analysis of ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$(e,e’p) and ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$(e,e’α) coincidence data, taken at three momentum transfers 0.39<q<0.68 ${\mathrm{fm}}^{\mathrm{-}1}$, yields both E1 and E2/E0 form factors and the respective multipole strength distributions in the giant-resonance region of ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ ($E_x$=14–22 MeV). While the deduced E1 strength agrees well with previous results, the total extracted E2/E0 strength is about twice the value found with isoscalar projectiles indicating the presence of large isovector E2/E0 contributions in the region of the isoscalar E2/E0 giant resonances.

Time-dependent Hartree-Fock theory is used to study fusion in ${}_{}{}^{16}{}_{}{}^{}$O${+}^{16}$O collisions. The Hamiltonian density is obtained from Skyrme forces including the spin-orbit interaction. The inclusion of spin has a dramatic effect on the observed dissipation for central collisions. At a center-of-mass energy of 34 MeV, fusion is found for all angular momenta less than the experimental critical angular momentum. Thresholds for inelastic scattering increase to a bombarding energy per nucleon of about 9 MeV. The decrease in transparency is in general agreement with experiment.

We demonstrate here the direct observation of quantum jumps between the $6^2$${\mathrm{S}}_{1/2}$ state and the $5^2$${\mathrm{D}}_{5/2}$ state of an individual laser-cooled ${\mathrm{Ba}}^{+}$ ions contained in a radio-frequency trap. The state detection and cooling are performed by two lasers which cause $6^2$${\mathrm{S}}_{1/2}$${\mathrm{-}6}^2$${\mathrm{P}}_{1/2}$${\mathrm{-}5}^2$ ${\mathrm{D}}_{3/2}$ transitions. Incoherent excitation to the $5^2$${\mathrm{D}}_{5/2}$ state (via the $6^2$${\mathrm{P}}_{3/2}$ level) causes the fluorescence from the $6^2$${\mathrm{P}}_{1/2}$ state to be suppressed for >30-sec lifetime of that state, after which the fluorescence reappears. The resulting ‘‘telegraph signal’’ provides a direct monitor of the atomic state.

The Bloch-Maxwell equations of quantum optics are examined as a potential model problem for erratic motion in convective flows. A new type of erratic motion is found in which discrete harmonics accumulate geometrically to form an unresolvable spectral continuum.

A laser light through a (spatially) random-phase plate generated a long–spatial-scale magnetic field from rippled surface irregularities. The field is 3–10 times larger than the thermoelectric field without the random-phase plate. A dynamo effect is proposed to explain the field enhancement as well as the thermoelectric-field dependence on the laser intensity.

An optical technique called induced spatial incoherence can produce the highly uniform laser beams required for direct-illumination laser fusion. Here we present experimental data on laser-plasma interactions showing that the technique, when used in combination with short laser wavelength, also improves the coupling physics.

An rf-stabilization experiment was performed in the axisymmetric single-mirror device HIEI by controlling the radial-gradient scale length of the rf field with the aid of an azimuthally phased antenna array. The flute stability depends sensitively on the scale length of the perpendicular rf electric field, which shows that rf stabilization is caused by the ponderomotive force for ions.

We present a new theory of dynamic correlations for a classical one-component plasma in strong Coulomb coupling within the generalized viscoelastic formalism. The dynamic structure factor and the coefficient of shear viscosity for the one-component plasma in a metastable supercooled state are investigated and the possibility of a glass transition is predicted. Relevance to laboratory experiment is pointed out through analyses of the metastable-state lifetimes against homogeneous nucleation of the crystalline state.

The role of chemical potentials in surface reconstructions is examined and shown to be crucial for binary semiconductor srufaces such as GaAs(111)2×2. We predict that under As-rich conditions a new model, the As triangle, is the lowest-energy geometry, whereas the Ga-vacancy model is appropriate for Ga-rich conditions. A change in the relative chemical potential of Ga and As should produce a phase transition between the two structures.

The growth of Xe films on Pt(111) has been investigated by elastic and inelastic, high-resolution, thermal-He scattering. Down to 25 K, Xe films grow layer by layer up to at least 25-monolayer films. This enlarges the complete wetting range on the so-called ‘‘scale of substrate strength’’ by a factor of 4. A buckling of the rotated monolayer has been observed for the first time. This demonstrates that the full monolayer is locked on the substrate and suggests that orientational ordering contributes to complete wetting on strongly binding substrates.

By the application of uniaxial stress, an allowed optical transition of chalcogen donors in silicon can be brought into near resonance with a forbidden transition. If the interaction coupling the two final states is strong enough, both transitions will become visible in absorption. We report here the first study of spin-triplet states of double donors, and our results indicate that many-electron effects are substantial in these systems.

A calculation of the coefficient $C_k$ of the terms linear in $\mathrm{k}$ in the ${\Gamma }_8$ valence bands of several III-V semiconductors is presented. On the basis of the systematics of these results it is concluded that these terms arise from coupling by the linear momentum and the spin-orbit operators to the uppermost $d$ levels of the core. A simple analytic expression to calculate $C_k$ for all III-V, II-VI, and I-VII compounds with zinc-blende structure is proposed. The results are in good agreement with the few experimental data available.

We analyze the critical behavior of isotropic ferromagnets with a free surface by means of field-theoretic renormalization methods in d=2+ε dimensions. Renormalization-group equations for surface quantities are derived which imply scaling to all orders in ε. Explicit results to order ${\mathrm{\epsilon }}^2$ are presented for the critical surface exponents of the ordinary transition. Interpolation with the known results near four dimensions yields estimates for d=3 which seem to be remarkably accurate.

Surface plasmons on opposite sides of a thin metal film can cross couple in the presence of a surface corrugation, or grating. We report the observation of this cross-coupling phenomenon as a radiative-decay mechanism for molecules near a corrugated thin metal film.

The ${\mu }^{+}$ Knight shift in rhombohedral Bi below 10 K is found to exhibit an anisotropy of solely fourth order in the direction cosines, or explicitly a ${sin}^2\left(2\mathrm{}\theta \right)$ dependence, where $\theta$ is the angle between the $c$ axis and the applied magnetic field. The implications of this dependence, allowed by symmetry arguments but never seen before in NMR studies, are discussed. In addition, the lattice site of the ${\mu }^{+}$ below 10 K has been determined and a local lattice contraction of approximately 11% was observed.