This Letter presents a general method for calculation of moments of invariant measure of multidimensional continuous-time dissipative dynamical systems with noise. In particular, moments of the Lorenz model are calculated.

Pattern observations and heat-transport measurements of convection in ethanol-water mixtures at positive values of the separation ratio $\psi$ are presented. Close to onset, the convective flow manifests itself in a stationary square pattern with negligible change in heat transport compared with the conductive state. Far from threshold, convection selects the usual roll structure with a strong change in heat transport. In a crossover region, the competition between square and roll patterns leads to oscillations.

The relativistic equations governing the nonlinear interaction of two light waves and a Langmuir wave are shown to admit two classes of solitary-wave solutions. Temporal solitary waves propagate at speeds greater than the speed of light and carry no information. Spatial solitary waves propagate at speeds less than the speed of light and do carry information. The properties of these waves are discussed and the spatial solitary waves are shown to be well suited to the beat-wave acceleration of particles.

The study of salt-free polyelectrolytes within the primitive model and with the hypernetted chain integral equation leads to a phase separation at very low concentration. The spinodal line and the critical point are deduced from the compressibility equation and are determined as functions of the polyion charge.

Binary Si:H alloys containing a number of polysilane ${\left(\mathrm{Si}{\mathrm{H}}_2\right)}_n$ groups have been produced by plasma chemical-vapor deposition of disilane. High-resolution electron micrographs of these alloys clearly show a number of lattice fringes, indicating that the polysilane groups are crystallized. The extended x-ray-absorption fine structures as well as the electron-diffraction patterns show that the Si atoms in the polysilane crystals occupy the same lattice points as those of tetrahedrally bonded silicon crystal.

We have carried out an ab initio theoretical study of the potential energy and molecular dynamics of ${\mathrm{Rb}}_2$Zn${\mathrm{Cl}}_4$. These calculations demonstrate that the incommensurate transition in this compound is caused by the relaxation of imperfect-hexagonal spirals of highly unstable Zn${\mathrm{Cl}}_4^{2-}$ ions. This leads to angstrom-size displacements with essentially zero energy change. We argue that such "latent" (or imperfect) symmetry could be the general cause of incommensurate transitions in insulators.

The cluster-mass distributions produced in the kinetic aggregation of aqueous gold colloids are measured over an extended range of masses for two limiting kinetic regimes, diffusion-limited (DLA) and reaction-limited (RLA) aggregation. Markedly different distributions are found, with DLA having a peaked distribution, while RLA has a power-law distribution. In both cases the distributions are shown to exhibit dynamic scaling, as has recently been predicted. The data are interpreted with the Smoluchowski equations, and are used to determine the form of the appropriate kernel for each regime.

Quasielastic and inelastic neutron scattering has been used to study the diffusion and the layer shear elastic constant across the melting transition of incommensurate K and Rb layers intercalated in graphite. The melting of the quasi two-dimensional layers on a periodic graphite substrate is characterized by a smooth transition from a solidlike to a liquidlike dynamical behavior via unpinning of discommensuration domain walls.

We report the observation of molecular ${\mathrm{H}}_2$ chemisorption at the edge sites of a stepped Ni (100) surface that is covered with a dense layer of atomic hydrogen. No such state is observed on the flat Ni (100) surface. We suggest that this ${\mathrm{H}}_2$ chemisorption state can form stably as a result of residual unfilled $d$ states at these step sites, while the dissociative channel is blocked by the saturated atomic adsorbate layer.

We report the first observation of weak localizations effects in light scattering by a disordered solid. For a diffuse solid scatterer we predict and observe (i) multiple backscattering speckle, (ii) a coherent backscattered peak remaining after removal of this speckle by ensemble averaging, and (iii) speckle statistics which differ from those for single scattering. Computer simulations based upon the theoretical equations yield results in good agreement with experiment.

Velocities of NO molecules scattered from Ag(111) have been measured as a function of rotational state for a wide range of incidence energies and angles. We find that increasing rotational excitation is accompanied by decreasing energy transfer to phonons. Results agree quantitatively with an extensive trajectory simulation employing a realistic multidimensional interaction potential, which shows that this correlation is mediated largely by the orientation angle of the colliding molecule. A simple kinematic model suggests that this behavior is a general feature of molecule-surface scattering.

We report a new approach to the study of electron spectral clustering and wave-function scaling in several one-dimensional quasiperiodic systems. The approach is based on renormalization-group ideas. We introduce a novel decimation technique which generates a simple physical picture of the electron spectral behavior and the nature of the wave functions. Our renormalization-group scheme is verified by the numerical computation of the probability density summed over the states belonging to the clusters and subclusters of the spectrum.

The electron-spin-resonance signal of metallic Si:P near the metal-insulator transition has been measured down to a temperature of 30 mK. The paramagnetic spin susceptibility and the resonance linewidth are found to increase sharply with decreasing temperature. We argue that these effects are due to the enhancement of spin fluctuations, and the accompanying slowing down of spin diffusion near the metal-insulator transition. The results are compared with the predictions of recent theories for the susceptibility and linewidth of disordered interacting-electron systems.

We prove experimentally that the band lineup at the Si${\mathrm{O}}_2$-Si interface can be modified by means of an intralayer. Hydrogen and cesium intralayers produce modifications of 0.5 and 0.25 eV in opposite directions. Possible explanations of these dramatic changes are discussed.

It is proposed that measurements of the isothermal pressure dependences of emission rates and capture cross sections can provide a quantitative measure of the lattice volume relaxation accompanying carrier capture and emission processes by deep levels. The method is demonstrated for the gold acceptor and the oxygen-vacancy pair ($A$ center) levels in silicon. The results represent what is believed to be the first quantitative determination of these relaxations for any deep levels in any semiconductor.

The formation of heavy-fermion bands is discussed on the basis of the relativistic Korringa-Kohn-Rostoker equation. It is shown that only one specific linear combination of six local $f$ states can hybridize with a conduction state of given $\mathbf{k}$ and spin. It follows that the magnetic moments of the heavy fermions are sharply quenched. The Wilson ratios calculated from these effective magnetic moments fit experimental data much better than without this correction.

Two hydrogen nuclei and a hole bind to the triple-acceptor copper in germanium. The result is a single acceptor whose electronic states are modified by coupling to the zero-point motion of the nuclei. That motion displays a qualitative change from rotation to libration induced by an increase in hydrogen isotopic mass. The acceptor $A\left(\mathrm{Cu}{\mathrm{H}}_2\right)$ has full tetrahedral symmetry and a complex ground-state manifold. All heavier isotope combinations display only a single ground-state component of symmetry lower than tetrahedral.

Using the photomodulation technique for iodine (${\mathrm{I}}_3^{-}$)-doped polyacetylene, we have found spectroscopic evidence for an abrupt phase transition at 5% ${\mathrm{I}}_3^{-}$. The transition is from the lightly doped phase best described as soliton lattice to the heavily doped metallic phase. The phase transition is characterized by gradual disappearance of the single photoinduced soliton band in the semiconducting phase and a sudden appearance of two correlated photoinduced absorption bands associated with photogenerated charged defects in the metallic phase.

The anomalous microwave absorption resonances recently observed in aqueous solutions of DNA are explained in terms of a layered structure of water molecules around the polymer. At high frequencies the interactions with water become elastic instead of viscous.

A model is proposed for the 5 March 1979 $\gamma$-ray transient. A small lump of strange matter, previously ejected from a supernova explosion, struck a slowly rotating strange star. This resulted in a high-intensity flash of radiation from a hot spot produced by the impact. The high-intensity radiation blew open a crater in the crust; the energy released as this crater refilled was responsible for the longer-duration, lower-intensity phase. The 8-s modulation is due to the rotation of the star. A plausible scenario for the production of this event is discussed.