The global phase diagram for wall and surface critical phenomena is analyzed in the space of temperature, surface enhancement, and bulk and surface fields, on the basis of Landau phenomenological theory. Features probably valid for various real systems are the physical unity of prewetting and pure surface criticality, and novel exponents for critical wetting and for a wetting tricritical point, which terminates the region of normal first-order wetting.

Partial dislocations are the most important intrinsic defects, other than point defects, in controlling the mechanical and electronic properties of silicon. From high-resolution electron-microscopy data, and a simple optimization procedure, a realistic geometry is presented for the 30° partial dislocation. Electronic structure calculations have been performed for this geometry and it has been established that no electrically active states are associated with this dislocation.

High-pressure x-ray diffraction experiments up to 30-40 GPa on lanthanum, praseodymium, and yttrium metals demonstrate that there is one more crystal structure in the regular rare-earth crystal-structure sequence. This structure results from a second-order phase transition in fcc phase and could be described by a zone-boundary soft phonon mode with $\overrightarrow{\mathrm{q}}=\left(\frac{2\pi }{a_0}\right)(\frac{1}{2}, \frac{1}{2}, \frac{1}{2})$.

Semi-infinite systems which undergo a first-order bulk transition are considered. A new type of surface phase transition is predicted which has two unexpected features: (1) It exhibits some universal properties since a variety of surface exponents can be defined although there are no bulk exponents; (2) a layer of the disordered phase appears between the free surface and the ordered bulk. The interface between the disordered and the ordered phases becomes delocalized as in the wetting and in the pinning transition.

In a study of the oxidation of methanol on Cu(100), the vibrational frequency of the C-O stretch mode of the methoxide is used to monitor the probability for a methanol molecule to react with a surface oxygen atom under different conditions. It is concluded that at least one empty nearest-neighbor adsorption site adjacent to the oxygen atom is necessary for the reaction. As the substrate temperature is raised the reaction probability is strongly reduced, because of an increased mobility of the methoxide molecules.

The position of the lowest empty orbitals of CO and O chemisorbed on Ni(111) have been determined by use of inverse photoemission in the ultraviolet. The $2{\pi }^{*}$ orbital of CO is lowered by 4.5 eV upon chemisorption and broadened to a 5.5-eV-wide resonance centered 3.5 eV above $E_{\mathrm{F}}$. Chemisorbed oxygen has sharp $2p_{x,y}$ states at 1.4 eV above $E_{\mathrm{F}}$ at $k_{\parallel }=0\mathrm{}$ with the total density of states extending from $E_{\mathrm{F}}$ to $E_{\mathrm{F}}+2\mathrm{}$ eV in agreement with band calculations. This state disappears upon oxide formation.

Free-atom-to-metal shifts of the rare-earth $2p$, $3d$, $4f$, and $5s$ core-level binding energies have been calculated. For Pr-Sm and Tb-Tm, elements which undergo a valence change on formation of the solid, the shifts are smaller and depend significantly on the $\mathrm{nl}$ core-state quantum numbers. Consequently, a unique shift characterizing all core levels of a given element cannot be assumed when a configuration change involving the $4f$ states occurs on solid formation.

The existence of a bound state between a crystal-field excitation and a low-lying phonon in Ce${\mathrm{Al}}_2$ is suggested. It can explain in a natural way the hitherto unexplained two-peak structure found in magnetic neutron-scattering experiments. Various checks are made to substantiate this suggestion. A similarity is pointed out to the exciton-phonon bound-state problem in semiconductors.

The scheme of bifurcations in systems described by a certain class of delay-differential equations is investigated in detail. It is shown that higher-harmonic oscillating states appear successively in the course of transition to developed chaos. First-order transitions between these states account for the frequency-locked anomaly recently observed by Hopf et al. in a hybrid optical bistable device.

Bell's theorem is formulated as a nonlocality property of quantum theory itself, with no explicit or implicit reference to determinism or hidden variables. A recent Letter on this subject is discussed.

Arguments are given against considering Bell's inequalities to be equivalent with determinism. Possible misinterpretations of the conflict between quantum mechanics and these inequalities are pointed out. With use of results obtained in previous papers on this subject, it is shown that locality rather than determinism is the issue.

Decays of $B$ mesons to kaons without charmed particles are shown to be sensitive to the top-quark mass, and therefore can be used to determine $m_t$ or at least to set limits on it. For $m_t\simeq 2M_W$ the inclusive branching ratio is about 2%, while for $m_t\simeq 20$ GeV it is only 0.4%. The flavor-changing transition $b\to s+\mathrm{gluon}$ is calculated and added to the penguin and the direct decay ($b\to u\overline{u}s$) contributions.

Molecular states are characterized by enhanced electromagnetic deexcitations of many different multipolarities. The expected enhancement of $E1\mathrm{}$, $E2\mathrm{}$, and $E3\mathrm{}$ transitions is examined deriving molecular sum rules for radiative deexcitation widths and via a dimensionality approach. The enhancement of the $E1\mathrm{}$ transitions is the most striking.

The Rostoker equation indicates that electrons with parallel velocities comparable to the ion thermal velocity have large interactions with ions even when they have large perpendicular velocities. A numerical study on test-electron behavior in velocity space demonstrates an anomalous parallel-velocity slowing as the result of this effect. The effect is prominent when the magnetic field is strong.

Electrostatic ion confinement is demonstrated in an rf-sustained tandem mirror and shown to have a dynamic nature. Measurements of plasma potential and ion end loss on particular flux tubes show that confinement can be enhanced by a factor of 3 over direct-flow loss rates. The axial confining potential can vary with radial position and time resulting in changes in ion confinement with abrupt reductions in central-cell plasma density when axial potential confinement is reduced.

Several novel electric field effects on superfluid helium-3 in the $A_1$ phase are proposed and analyzed which are based on the one-spin nature of this superfluid. It is shown that a steady-state superflow can generate an electric field distribution outside the superfluid channel, and an ac electric field can drive a fourth sound in this superfluid. Both effects are very weak, but seemingly detectable with present-day instrumentation.

The crystallization of a Lennard-Jones liquid has been studied with molecular-dynamics techniques. In particular, the motion of the fcc (100) interface has been measured for a range of temperatures below the melting point. The crystallization rates are not limited by the mobility of atoms in the bulk liquid; measurable rates are even observed below the glass transition temperature. This result suggests the existence of a class of materials which is qualitatively different from conventional glass-forming materials.

ac-Josephson junctions of tin and lead were found to emit monochromatic phonons with Josephson frequency, rather than thermal phonons. This is a new tunable phonon source with high efficiency and prospectively extremely high frequency resolution.

Pulsed-NMR measurements of methane on graphite have been performed between 45 and 105 K for 0.2 to 1.1 monolayers. Spin-relaxation times show first-order melting at 57 K, sensitivity to the hypercritical fluid, and continuous transitions where an incommensurate solid displaces the registered phase at both higher temperature and coverage. These measurements, plus activation-energy comparisons, provide a significant clarification of methane's high-temperature behavior.

The anisotropy of $\mathrm{Cu}\mathrm{Mn}$ spin-glasses was probed by torque measurements. In $\mathrm{Cu}\mathrm{Mn}$ (20 at.%) the anisotropy is $2\pi$ periodic, increasing to its maximum when the spin system is rotated by $\pi$ away from equilibrium. After a rotation by $\pi$ around $\hat{x}$, the anisotropy energy remains at its maximum value during a subsequent rotation around $\hat{y}$ (perpendicular to $\hat{x}$), at least in a limited angle range. These properties are due to the existence of antisymmetric interactions.