A technique for directly measuring the static structure factor for electrons with use of synchrotron radiation is described. Results for the conduction electrons in beryllium and the basal plane of graphite show a peak at $k\cong 2k_{\mathrm{F}}$ as predicted, but the pair correlation function shows an anomaly at distances considerably shorter than the mean interparticle separation.

A relationship between the Kosterlitz-Thouless transition temperature $T_{\mathrm{KT}}$ and the sheet resistance ${R_{\square }}^N$ of a granular superconducting film is derived taking into account the electrostatic charging energy. The zero-point phase fluctuations produce a drop of the areal superfluid density at a critical value of the sheet resistance in agreement with the recent observation on granular lead films.

High-resolution angle-resolved photoelectron emission spectra for Ni(100) are reported which identify a magnetic surface state just below the Fermi level. This surface state exists throughout the surface Brillouin zone including the zone-center $\overline{\Gamma }$ where its room-temperature binding energy and intrinsic width are 0.11 and 0.15 eV, respectively. These new results provide additional insight into the long-standing electron-spin polarization-sign-reversal controversy.

A partial Meissner effect, fully diamagnetic shielding signals, and large anisotropies in the upper and lower critical fields in ditetramethyltetraselenafulvalene-hexafluorophosphate [${\mathrm{}\left(\mathrm{TMTSF}\right)\mathrm{}}_2$P${\mathrm{F}}_6$] under applied hydrostatic pressure are observed.

Island growth and orientational locking in stage-2 potassium-intercalated graphite is observed by real-space imaging and electron diffraction on single crystallites. A mechanism is presented, relating these two phenomena. For $86\lesssim T\lesssim 130$ K, intercalate islands of incommensurate ordering are orientationally unlocked from the graphite lattice, as indicated by ring diffraction patterns. With increasing temperature, gradual island growth is by accretion. A threshold size (∼50 Å reached at 130 K) triggers precipitous island growth by coalescence and orientational locking.

Electron spin relaxation measurements on low-spin ${\mathrm{Fe}}^{3+}$ in several proteins show that they occupy a space of fractal dimensionality $d=1.65\mathrm{}\pm 0.04$, in conformity with the dimensionality $d=\frac{5}{3}$ of a self-avoiding random walk. Analysis of myoglobin x-ray data independently confirms this fractal dimension.

The possibility is investigated that the decay of massive cosmological neutrinos may have produced a spectral signature which has already been detected in observations of the ultraviolet background radiation. Various implications are discussed including a possible implied neutrino mass of 13.8-14.8 eV. A lower limit is also placed on the lifetime of heavy neutrinos ${\nu }_H$ with respect to the decay ${\nu }_H\to {\nu }_L+\gamma$ based on the cosmic uv observations.

This Letter reports indications of neutrino instability obtained from data taken on the charged- and neutral-current branches of the reaction ${\overline{\nu }}_e+d\{\nearrow n+n+e^{+},(\mathrm{cc}d\left)\right\}\{\searrow n+p+{\overline{\nu }}_e,(\mathrm{nc}d\left)\right\}$ at 11.2 m from a 2000-MW reactor. These results at the (2-3)-standard-deviation level, based on the departure of the measured ratio ($\frac{\mathrm{cc}d}{\mathrm{nc}d}$) from the expected value, make clear the importance of further experimentation to measure the ${\overline{\nu }}_e$ spectrum versus distance.

It is shown that massive transfer reactions emitting energetic light particles can be described in terms of two-step processes, in which breakup of the projectile takes place first, followed by an absorption of the massive partner of the broken-up pair by the target.

Analyzing-power data for excitation of states in ${}_{}{}^{90,92}{}_{}{}^{}\mathrm{Zr}$ by 160-MeV protons show striking differences, especially for the first $4^{+}$ states. Coupled with considerations of the structure of these states and the $N-N$ $t$ matrix these data strongly suggest that such measurements should provide a sensitive probe of the participating shell-model configurations and their isospin constituency. Data for the $8_1^{+}$ state in ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$ establish the dominant role of the $N-N$ $\overrightarrow{\mathrm{L}}·\overrightarrow{\mathrm{S}}$ force in the excitation of high-spin natural-parity states.

It is confirmed that the 3489-Å transition observed in beam-foil excited lithium spectra originates from the negative lithium ion. It is most probably the transition $1s2s2p^2{}_{}{}^5{}_{}{}^{}P-1s2\mathrm{}{p}^3{}_{}{}^5{}_{}{}^{}S_{}^{\circ }{}_{}{}^{}$, as suggested by Bunge. A new electric field acceleration technique provides identification of the charge state of the emitting ion. The decay curve is a cascade-free single exponential. The polarization and beam energy dependence of the light yield have also been measured. The transition has been identified in heavier isoelectronic ions.

It is shown that a single-mode laser under the influence of an external modulated field may show chaotic behavior. The power spectrum and the separation distance are calculated to demonstrate the existence of chaos.

Theory shows that to explain the polarization of light collisionally redistributed from the far line wings of an atomic transition, one must consider correlated events in which absorption during a collision, and propagation to the final Zeeman-state superposition at the end of the collision is important. Polarizations of up to about 40% have been measured in the far line wings, substantially confirming this prediction, and showing that scattering experiments cannot just be characterized by simple absorption or emission profiles.

Numerical calculations of the ion thermal conductivity in helical toroidal (torsatron) magnetic configurations show the presence of a plateau regime extending over two orders of magnitude in collision frequency, $\nu$. The value of the ion thermal conductivity is approximately equal to the neoclassical plateau value for an equivalent torus without helical modulation. The predicted adverse $\frac{1}{\nu }$ behavior due to ripple trapping is not seen.

The transverse and longitudinal sound velocities in amorphous and recrystallized Ga films were measured by tunable monochromatic phonons. The transverse sound velocity was found to be smaller by a factor of 2.8 in the amorphous phase, while there was no significant change for longitudinal phonons. Comparing the result with specific heat data gives no evidence for the existence of localized states.

The heat-capacity anomaly caused by phasons—the collective excitations of an incommensurate charge-density wave—is identified in rubidium metal at 0.8 ${}_{}{}^{\mathrm{o}}{}_{}{}^{}\mathrm{K}$. Data analysis leads to a value ${\Theta }_{\varphi }=4.5\mathrm{}°$K for the phason cutoff frequency. The velocity ratio of a purely longitudinal to a purely transverse phason is found to be ∼11.

The heat capacity under saturated vapors, $C_{\sigma }$, of three different concentrations of NaN${\mathrm{H}}_3$ solution ($X=0.045, 0.046, 0.063$ molar part of Na) has been measured in the temperature range 200-300 K. All three $C_{\sigma }\mathrm{}\left(T\right)\mathrm{}$ curves show anomalies consistent with the existence of a new two-phase region above the well-known liquid-liquid critical point ($X_c=0.0415\mathrm{}$, $T_c=232\mathrm{}$ K). Its location is compatible with the metal-nonmetal transition line; so it is believed that in equilibrium these are metallic and insulating phases with different concentrations of electrons.

The low-temperature (1.3 to 20.0 K) heat capacity of the strongly Pauli-paramagnetic Lu${\mathrm{Co}}_2$ compound was measured in magnetic fields up to ∼10 T. The measured results show that the electronic-specific-heat constant decreases with increasing magnetic field (11% at 10 T), while the Debye temperature does not change. This is probably due to the depression of spin fluctuation enhancement of the heat capacity by moments induced on the cobalt atoms by the high magnetic fields. These results appear to be in accord with recent theoretical predictions.

A thermal-neutron inelastic scattering kernel based on recently observed collective motion in liquid hydrogen, taken to be of quasicrystalline nature with an appropriate chemical binding energy, is found to explain the experimental pulsed neutron and steady-state spectra studies at 20 K. Thus the collective motion plays a very significant role in the transport of low-energy thermal neutrons in liquid hydrogen.

The nongeminate recombination of photogenerated holes in undoped $a$-Si: H has been studied by the delayed-collection-field technique. The analysis of experimental data indicates that the bulk and surface losses of holes involve extremely slow processes with temperature dependences similar to that of their drift mobility. The results indicate that the recombination lifetime is remarkably long (>10 msec) at room temperature. When the same analysis is applied to the photoinduced absorption data of Vardeny et al., the carrier involved can be identified as the electron, and a similar conclusion regarding carrier loss is reached.