A proton-proton coincidence experiment has shown that, following the superallowed beta decay of the odd-odd, $T_z=-2\mathrm{}$ nuclide, ${}_{}{}^{22}{}_{}{}^{}\mathrm{Al}$, two protons are emitted with a summed energy spectrum (5.636, 4.139 MeV) characteristic of decay to the ground and first excited states of ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$, respectively.

An explanation in terms of solitons is given for the recent observation by Galin et al. that the linear momentum transfer in ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$-induced heavy-ion reactions is limited.

A new method to determine dynamic effective moments of inertia at high rotational frequencies is presented. The very large values found at the highest spins ($50\hslash -55\mathrm{}\hslash$) in some Er and Yb nuclei are most likely explained by the alignment of high-$j$ proton orbitals, and could imply triaxial shapes.

The absolute total cross section for the reaction ${}_{}{}^7{}_{}{}^{}\mathrm{Be}(p, \gamma ){}_{}{}^8{}_{}{}^{}\mathrm{B}$ has been measured for $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=117-1230\mathrm{}$ keV by detecting the delayed $\alpha$ particles following the ${}_{}{}^8{}_{}{}^{}\mathrm{B}$ $\beta$ decay. Two independent methods have been used to determine the areal density of the ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ target. The inferred zero-energy $S$ factor from the present experiment is $S_{17}\mathrm{}\left(0\right)=0.0216\mathrm{}\pm 0.0025$ keV b. This value reduces the predicted ${}_{}{}^{37}{}_{}{}^{}\mathrm{Cl}$ solar-neutrino capture rate by ∼25%.

A quantum electrodynamic treatment of an autoionizing atom excited by a laser field is presented. As the main result, the authors present the average number of photons emitted into a particular mode of the electromagnetic field. In the case of a symmetric autoionizing resonance, the spectrum presented here resembles the power spectrum in resonance fluorescence of a two-level atom. For an asymmetric resonance, however, this spectrum manifests the confluence of coherences. The total number of scattered photons has a maximum at the confluence intensity. The spectrum is asymmetric in this case.

Thomson-scattering measurements of ion fluctuations driven by stimulated Brillouin scattering in a C${\mathrm{O}}_2$-laser-plasma interaction experiment are reported. It is found that the ion fluctuations correspond to a heavily damped, convective model of the Brillouin instability. The dominant $2k_0$ wave number ($k_0$ is the C${\mathrm{O}}_2$-laser wave number) for the ion fluctuations is confirmed, with no evidence for harmonic generation. Growth and decay times of the ion fluctuations were found to be relatively long, ∼150-700 ps, consistent with heavy wave damping.

The onset of solidification of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ in porous Vycor is identified from changes in transverse sound velocity. From observed overpressures required to initiate freezing (ranging from 18 bars at 1.3 K to 30.7 bars at 2.38 K), the interfacial energy between liquid and solid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ was estimated. The superfluid transition up to 35.5 bars was also observed.

Continuous and planar single-crystal Ni${\mathrm{Si}}_2$ films (< 60 Å thick) have been grown on Si(100) and (111) by ultrahigh-vacuum techniques. Nickel deposition (< 20 Å) on atomically clean Si at room temperature, followed by low-temperature heating at ∼450°C, results in the growth of epitaxial Ni${\mathrm{Si}}_2$ films whose structure depends critically on the starting Ni thickness. The films are coherent, without misfit dislocations. The orientation of the (111) silicide can be controlled by the initial Ni thickness.

The thermal expansion of an amorphous metal (${\mathrm{Pd}}_{0.775}$${\mathrm{Si}}_{0.165}$${\mathrm{Cu}}_{0.06}$) has been measured between 1.5 and 350 K. A negative thermal-expansion coefficient is observed at low temperatures. This arises from a huge negative Grüneisen parameter which is attributed to tunneling states.

Two induced-absorption lines from the upper- and the lower-branch excitonic polaritons to the excitonic molecule were observed in CuCl near the longitudinal exciton energy. The ratio of the intensity of the induced absorption from the lower-branch polariton to that from the upper-branch polariton was 0.8±0.2 near the longitudinal exciton energy and this value decreased with the increase of the excitation photon energy. These results can give a new approach to the determination of the additional boundary conditions.

The recently proposed model Hamiltonian for a linearly conjugated diatomic polymer is studied in the continuum limit in which there emerges a field-theoretic Dirac Hamiltonian, exhibiting charge fractionization into irrational numbers, just as in the discrete model.

Surface states were detected with sub—band-gap electroreflectance spectroscopy in the presence of electrolytes that can adsorb on the surface of Ti${\mathrm{O}}_2$. The energy of these states is located 1.3 eV below the conduction band and they can be detected only in the weak accumulation mode. The potential distribution at the interface as a function of the electrolyte was investigated by impedance spectroscopy. These results were interpreted in terms of "intrinsic" surface states of the unsolvated surface.

Resonance ionization followed by Auger neutralization is the mechanism for deexcitation of metastable noble-gas atoms (He, Ne, Ar) at metal surfaces which are either clean or covered with "small" atomic adsorbates and whose work function is ≳ 4.5 eV. The energy distributions of the emitted electrons reflect the self-convolution of the local density of states of the outermost atomic layer and thus provide a spectroscopic technique with extreme surface sensitivity as demonstrated with Pd(111) and Cu(110) surfaces.

The $\frac{1}{f}$ noise of platinum films and ultrathin platinum wires has been found to scale inversely with the number of atoms in the sample, $N$, for $N$ in the range ${10}^7$ to ${10}^{14}$. This strongly reinforces the idea that the $\frac{1}{f}$ noise of continuous metal films is of bulk origin, and demonstrates that the dominant form of excess low-frequency noise in the very small structures investigated here is the bulk $\frac{1}{f}$ noise.

The reflectivity of silicon has been measured following excitation with intense 90-fsec optical pulses. These measurements for the first time clearly resolve in time the process of energy transfer to the crystal lattice and the dynamics of the phase transition to the melted state.

The conventional thermodynamic fluctuation theory does not include local correlations and, hence, fails at volumes of the order of the correlation volume ${\xi }^d$. In this paper, an attempt is made to include local correlations in a thermodynamic theory by considering fluctuations in a sequence of concentric systems of decreasing volume. Tests are made on fluctuations in the magnetization within the one-dimensional Ising model. The results are a clear improvement over those of the conventional theory.

A statistical-mechanical model is proposed and solved exactly for the pair correlation function of planar uniaxial ferromagnets in the scaling limit, both with and without external magnetic field.

The field equations of $N=1\mathrm{}$ supergravity in $d=11\mathrm{}$ dimensions admit a spontaneous compactification on the seven-sphere to an $N=8\mathrm{}$ theory in $d=4\mathrm{}$ with local SO(8) invariance. A spontaneously broken version of this theory is provided by another solution of the field equations for which the metric on $S^7$ is distorted. The isometry group of this new solution is SO(5) ⊗ SU(2), the relevant holonomy group is $G_2$, and the $N=8\mathrm{}$ supersymmetry is broken down to $N=1\mathrm{}$ at the Planck scale. The implications for grand unified theories are briefly discussed.

A nonlinear differential equation for the asymptotic decay of the pair correlation function of a fluid at its critical point is obtained from the square-gradient theory (and its extension to fourth order), and analyzed when the critical exponent $\eta$ is either zero or nonzero. Its solutions are shown to be consistent with the correct power-law decay if and only if the ordinary scaling relations together with hyperscaling (for $\eta >0\mathrm{}$) are valid.

A measurement of the diffractive ${\psi }^{\prime }$ photoproduction cross section is presented. The ratio of the ${\psi }^{\prime }$ photoproduction cross section to the $\psi$ photoproduction cross section is found to be 0.20 ± 0.05 at an average energy of 150 GeV. With vector-meson dominance, the ratio of ${\psi }^{\prime }$-nucleon to $\psi$-nucleon cross sections is 0.75 ± 0.12.