The peak at ${\epsilon }_{\mathrm{F}}-0.3\mathrm{}$ eV seen in field-emission energy distributions for the (100) plane, which is quenched by H, O, and Kr, is not quenched by Au adsorption up to slightly above monolayer coverages. The peak does disappear abruptly at $\frac{\mathrm{Au}}{\mathrm{W}}>~1.15$ where a spontaneous rearrangement of Au out of the W lattice sites seems to occur. This suggests a surface resonance which can be transferred to the outermost layer, even if this is not W, as long as the potertial seen by the bulk electrons is sufficiently tungstenlike.

Resolved critical point structures in Schottky-barrier electroreflectance spectra of $\mathrm{Ga}3d^V$-$s{p}^3$ conduction band transitions in the 20-22-eV range provide a direct proof that the $L_6^{}{}_{}{}^C$ equivalent minima lie approximately 170±30 meV below the $X_6^{}{}_{}{}^C$ minima in GaAs. This ordering, opposite to that assumed and apparently supported by previous experiments, is in fact consistent with these experiments and provides natural explanations for many formerly puzzling features of GaAs.

Drude edges are observed in reflectance spectra and compared with the dc transport measurements in the lamellar compounds ${\mathrm{C}}_{6n}\mathrm{H}{\mathrm{NO}}_3$ with $n=1, 2, \mathrm{and} 3$. Both measurements confirm the general metallic character of these materials, but the optical data are inconsistent with a simple Drude model. We suggest that this is due either to a complex background dielectric constant or to a multiple-carrier Fermi surface.

The transition temperature $T_c$ of the displacive phase transition in SnTe as a function of the carrier concentration $p^{*}$ is determined by measurements of the resistance anomaly. The transition temperature $T_c$ decreases gradually with increasing $p^{*}$ and vanishes at $p^{*}\sim 1.3\times {10}^{21}$ ${\mathrm{cm}}^{-3\mathrm{}}$. The results are explained by the electron-TO-phonon interaction model with an optical-deformation-potential constant of 10 eV.

Photoelectron distribution curves of (110) single-crystal faces of the noble metals Cu, Ag, and Au obtained at photon energies of 16.85 and 21.22 eV show strong contributions which cannot be accounted for by direct $k$-conserving transitions. Instead we observed a surprisingly good correlation between the measured spectra and the one-dimensional density of states of the bulk band structure. It is supposed that surface photoemission is responsible for the observed effect.

An exactly soluble model for a spin-glass phase transition is presented. It is essentially a mean-field theory; but instead of "bond" randomness of the exchange interaction (as used by other authors), a "site" randomness is assumed. This enables one to calculate the "quenched" free energy without any uncertain mathematical procedures. Typical results are given for a variety of interesting cases.

We present the first complete theory of the effect of collisions between charge carriers on the electrical resistivity of a simple degenerate semimetal. We find that (i) electron-hole scattering can explain the anomalous $T^2$ resistivity of stoichiometric ${\mathrm{TiS}}_2$, (ii) elsetron-electron and hole-hole scattering do not contribute to $\rho$, and (iii) the theory of electron-hole scattering predicts that the resistivity of nonstoichiometric ${\mathrm{TiS}}_2$ should fall significantly below $T^2$ at high temperatures.

Renormalization group ideas are applied to the problem of first-order phase transitions in Ising-like models. They support the existence of essential singularities as the coexistence region is approached, at all temperatures below the critical temperature.

Lattice-gas phase boundaries have been calculated for the simple quadratic and honey-comb lattices from the corresponding antiferromagnetic critical curves. Results were obtained using nonlinear renormalization group methods with periodic cell clusters. The result for the simple quadratic lattice is in excellent agreement with the existing temperature-series result.

We report results of a $\pi N$ partial-wave analysis for $I=\frac{3}{2}$ resonances observed in the 1900-MeV region: $F_{35}\mathrm{}\left(1885\right)\mathrm{}$, $F_{37}\mathrm{}\left(1945\right)\mathrm{}$, $P_{31}\mathrm{}\left(1940\right)\mathrm{}$, and $D_{35}\mathrm{}\left(1925\right)\mathrm{}$. The $D_{35}\mathrm{}\left(1925\right)\mathrm{}$ is difficult to accommodate in conventional baryon models; we discuss an alternative model having such a state.

We have observed 22 events of the process $\overline{\nu }p\to \overline{\nu }p$ with a background expectation of 8 events. The neutral-current-to-charged-current ratio $\frac{\sigma (\overline{\nu }p\to \overline{\nu }p)}{\sigma (\overline{\nu }p\to {\mu }^{+}n)}$ is measured to be 0.2±0.1 for $0.3<\mathrm{}{q}^2<0.9\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$, where $-q^2$ is the square of the four-momentum transfer to the proton. When combined with our previous measurement of $\nu p\to \nu p$, this yields a ratio $\frac{\sigma (\overline{\nu }p\to \nu p)}{\sigma (\nu p\to \nu p)}=0.4\mathrm{}\pm 0.2$, where the error is statistical, suggesting that a purely vector, neutral, hadronic current is unlikely.

We report measurements of the inclusive electroproduction reaction $\mathrm{ep}\to e{\pi }^{+}X$ for pions produced at 90° in the virtual-photon-proton center-of-mass system. Data are presented at the ($W,Q^2$) points (2.2 GeV, 1.2 ${\mathrm{GeV}}^2$), (2.2,3.6), (2.65,1.2), (2.65,2.0), (2.65,2.8), (2.65, 3.6), (3.1, 1.2), and (3.1, 2.0). The invariant structure function is studied as a function of $W$, $Q^2$, $x_T$, $p_T^{}{}_{}{}^2$, and the square of the invariant undetected mass.

Using the harmonic-oscillator charmed-quark model, I have studied the electromagnetic mass differences and the decay rates of charmed mesons.

It is proposed that $\mathrm{CP}$ nonconservation arises purely from the exchange of Higgs bosons.

A relativistic oscillator model gives an expression for meson emission as a function of the fractional de-excitation $\alpha$, $k_{\perp }^{}{}_{}{}^2$, and the meson mass. From this, a form for $〈k_{\perp }^{}{}_{}{}^2〉$ in terms of $z$ is derived; it agrees with electroproduction experiments. The same expression predicts enhanced single-photon and, thereby, anomalous charged-lepton pair production.

Based on the shell corrections obtained from an extrapolated potential, the superheavy nucleus 126 in a spherical configuration does not appear to have a half-life as long as the age of the universe. Hartree-Fock calculations with Skyrme interactions do not reveal extra stability for element 126 ($A=354\mathrm{}$). There is thus the possibility that the primordial superheavy element 126 observed by Gentry et al may not be spherical. The distinction between spherical and toroidal shapes can be made by measuring the mass number of the observed superheavy element.

Double-differential cross sections have been measured for high-energy $p$, $d$, $t$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$, and ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ particles emitted from uranium targets irradiated with ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ ions at energies of 250, 400, and 2100 MeV/nucleon and ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ ions at 400 MeV/nucleon. By using the shape and yield of the proton energy spectra, the shape and yield of the $d$, $t$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$, and ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ energy spectra can be deduced at all measured angles for all incident projectile energies by assuming that they are formed by a coalescence of cascade nucleons, using a model analogous to that of Butler and Pearson, and Schwarzschild and Zupančič.

Angular distributions of transitions to low-lying states in ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ have been measured for the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({}_{}{}^{12}{}_{}{}^{}\mathrm{C},\alpha )$ in 62.5-keV steps for $6.5<~E_{\mathrm{c}.\mathrm{m}.\mathrm{}}<11\mathrm{}$ MeV. Two new nonstatistical structures are identified at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=7.71\mathrm{} \mathrm{and} 9.84$ MeV, with $J^{\pi }=4^{+} \mathrm{and} 8^{+}$, respectively. These observations support the quasimolecular interpretations of the low-energy structure in the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$-${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ interaction.

The momentum distribution of $p_{\frac{1}{2}}$ shell nucleons in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ is deduced from measurements of the angular distribution of the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}(\gamma ,p_0)$ reaction cross section between $E_{\gamma }=40\mathrm{} \mathrm{and} 105$ MeV. The results are found to deviate from the Elton-Swift distribution.

A variational principle is used to determine the binding energy and the fundamental vibrational frequency of ${\mathrm{H}}_2^{+}$ in the presence of magnetic fields of strengths found in some neutron stars. It is shown that for $B\sim {10}^{12}$ G the vibrational frequency lies in the ultraviolet or soft-x-ray part of the spectrum.