A new value for the deuteron binding energy of B(d)=2.388 176 8(24)×${10}^{\mathrm{-}3}$ u is reported based on an absolute wavelength determination of the 2.2-MeV n-p capture γ ray. Derived values of the n-H and n-p mass differences are also given. We also derive $M_n$=1.008 664 919(14) u. We note that the uncertainties in the neutron-mass data are now dominated by uncertainties arising from mass spectroscopy.

An interference between electric quadrupole and Stark induced dipole amplitudes is observed for the first time. Measurement of this interference in atomic strontium permits the first experimental determination of the decay rate between the lowest ${}_{}{}^1{}_{}{}^{}\mathrm{P}$ and metastable ${}_{}{}^1{}_{}{}^{}\mathrm{D}$ levels in an alkaline-earth atom. We obtain the result A(5s5p-5s4d)=(3.85±0.94±0.5 3)×${10}^3$ ${\mathrm{s}}^{\mathrm{-}1}$.

We have observed the Kapitza-Dirac effect in the scattering of sodium atoms by a nearly resonant standing-wave laser field. The data clearly show diffraction peaks of the atomic momentum transfer at even multiples of the photon momentum. Theoretical predictions for an off-resonant, adiabatic interaction with a two-state system are in reasonable agreement with the data.

An induction accelerator system has been successfully operated to postaccelerate an intense pulsed ion beam that is highly space-charge and current neutralized. An annular ion beam (energy 90 keV, current 5.7 kA, pulse width 750 nsec) extracted from an applied-${\mathrm{B}}_{\mathrm{r}}$ magnetically insulated diode is injected into the induction accelerator, where a short pulse (210 kV, 50 nsec) is applied. Measurements of beam energy by a Thomson-parabola spectrometer before and after the postacceleration have confirmed the increase in beam energy of ${\mathrm{H}}^{+}$ up to ∼240 keV after being postaccelerated.

Steady-state electron currents were driven by fast waves with ${\omega }_{\mathrm{ci}}$≪ω≪${\omega }_{\mathrm{ce}}$ in an initially current-free plasma in the Irvine Torus. Current direction was controlled by the fast-wave phased-array antenna. Low power experiments (<25 W) generated up to 1.3 A of electron current with a peak effeciency of η=InR/P≃(6×${10}^{\mathrm{-}2}$ A/W)(${10}^{13}$ ${\mathrm{cm}}^{\mathrm{-}3}$)m. Up to 14% of the wave energy was converted to poloidal magnetic field energy.

A statistical theory of strong Langmuir turbulence based on self-similarly collapsing cavitons is tested in one spatial dimension by study of the solutions of a set of nonlinear equations which includes, as a special case, the Zakharov equations. Single-caviton solutions exhibiting predicted self-similar collapse are verified numerically for special initial conditions. Multiple-caviton systems are studied over many generations of collapse. Long-time–averaged spectra do not contain the power-law inertial regime predicted by the theory because of nucleation at small scales.

Experimental spheromak magnetic equilibria are measured which differ significantly from the minimum-energy state, and are well described by a numerical model where $j_{?}$/B has a linear dependence on the poloidal flux function. Equilibria are determined in a nonperturbing manner by the combination of measurements of flux-conserver image currents with calculations from this model. These equilibria are corroborated by the observation of nondisruptive rotating internal kink distortions (with toroidal mode numbers n=1, 2, and 3), coupled with theoretical thresholds for the onset of these modes.

A strong magnetic field of 600 kG (60 T) is generated at the center of a 2-mm-diam one-turn coil in which the current is driven by a ${\mathrm{CO}}_2$ laser. The magnetic field, current, and voltage are measured as functions of the separation distance of the gap where the high voltage is induced by the laser irradiation in the coil loop at a fixed intensity of 1.3×${10}^{14}$ W/${\mathrm{cm}}^2$. These results are analyzed on the basis of hot-electron E×B drift and plasma expansion inside the gap. The analysis indicates how to design the target and the laser pulse for generation of a magnetic field of a few megagauss.

The domain growth in a two-dimensional twofold-degenerate system with soft domain walls is shown to obey dynamical scaling. The value of the growth exponent is n≃0.25 which differs from the classical Lifshitz-Allen-Cahn prediction n=(1/2), but accords with recent findings for other growth models with soft walls. The results suggest that domain-wall softness may be more important than the degeneracy of the ground state for a possible universal classification of domain-growth kinetics.

We analyze numerical studies of the harmonic measure of diffusion-limited aggregates in two dimensions by modeling this measure by a fractal set of singularities. We discuss the relationship between the dimension of this fractal set and the strength of the singularities, and the implications of these ideas both for the dimension of the entire aggregate and also for a more complete theory of diffusion-limited aggregation.

This paper report absolute free-energy calculations of the fluid, body-centered-cubic, and face-centered-cubic phases of helium at T=327.04 K. We find that at and around this temperature the model potential proposed by Aziz et al. doe not yield a stable bcc phase. Quantum corrections do not alter this conclusion.

The positions of atoms in icosahedral crystals are shown to correspond to arrangements of three-dimensional hypersurfaces in six-dimensional periodic lattices. The six-dimensional space-group symmetry allows for crystals which cannot be formed by space-filling decorated tilings (quasicrystals). Structures with continuously varying ‘‘unit cells’’ are possible. The connection between tilings, projections, cuts, and density-wave descriptions is pointed out.

It is shown that a determination of critical exponents in surface phase transformations based on a kinematic analysis of LEED peak intensities is subject to errors caused by multiple scattering that are large enough to prevent a clear assignment to a known universality class. The multiple-scattering contribution arises from short-range flucutations and has its maximum value at the transition temperature. The specific-heat exponent of the surface phase can be measured directly from the variation of the integral-order-beam intensity with temperature that is caused by the multiple scattering.

Three different calculations are carried out to treat the low-temperature dynamics in diluted d-dimensional Ising systems near the percolation threshold. All three use recursive methods based on a domain-wall–diffusion picture. The standard form of bicritical dynamic scaling is found to be violated for d>1. A quadratic dependence of the logarithm of the characteristic decay time on the logarithm of the correlation length is found and related to recent experimental work.

A semiclassical path-integral approach is used to calculate the contribution of large correlated ring exchanges to the energy of a two-dimensional Wigner crystal in a strong magnetic field. This correlation energy $E_c$(ν) shows cusps at fractional fillings ${\nu }_c$=n/m of the lowest Landau level. The uniform Wigner crystal is locally unstable for ν≠${\nu }_c$ and the theory predicts the existence of fractionally charged quasiparticles to accommodate the extra density ν-${\nu }_c$.

We report self-consistent, geometry-optimized, total electronic energy calculations for a K overlayer on a Si(001)-(2×1) surface. Our theory for metallization of the overlayer and dimensionality of collective excitations is different from previous suggestions and can successfully account for the experimental findings about this system. The metal-insulator transition is proposed to have its origin in active dangling bonds and not in the conventional Mott transition. We find a strong ionic type of binding between the overlayer and the substrate.

One-electron energies which approximate proper atomic electron-removal energies are constructed by post-hoc correction of bare local-spin-density–approximation eigenvalues (which are poor approximations to ionization potentials). The corrections give the proper atomic H limit, come decently close to the self-interaction–corrected eigenvalues, and only require quantities generated in routine self-consistent-field local-spin-density calculations.

It is shown that the localization length of quasienergy eigenfunctions is determined by the classical diffusion rate: l=D/2. The new numerical method of minimal Lyapunov exponent for the calculation of l is proposed and applied to the quantum standard map and Lloyd model.

We have found quantum chaos in a system consisting of two levels coupled through a time-dependent perturbation, when this perturbation is quasiperiodic with two incommensurate frequencies. This contrasts with the case of a monochromatic perturbation where the oscillations of the physical observables are nonchaotic, because of the Floquet theorem. The existence of chaos is confirmed by the observation of rapidly decreasing autocorrelation functions, and by a continuous Fourier spectrum for time-dependent fluctuations of physical observables.

This Letter reports a search for the production by $e^{+}$$e^{\mathrm{-}}$ annihilation of a single photon accompanied by particles that interact only weakly in matter. The search was performed at the SLAC $e^{+}$$e^{\mathrm{-}}$ storage ring PEP (√s =29 GeV) with a new detector, ASP. No unexpected signal was observed. The limit $N_{\nu }$<14 (90% C.L.) is placed on the number of light neutrino species, and the mass of scalar electrons predicted by theories of supersymmetry is constrained to $m_{ẽ}$>51 GeV/$c^2$ (90% C.L.) for $m_{\gamma ̃}$=0 and degenerate ẽ mass states.