We have measured the reaction ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$)${}_{}{}^{212}{}_{}{}^{}\mathrm{Po}$ at $E_{{}_{}{}^{16}{}_{}{}^{}\mathrm{O}}=93\mathrm{}$ MeV; the peak cross sections leading to the ground and first excited states of ${}_{}{}^{212}{}_{}{}^{}\mathrm{Po}$ are 750 and 1750 nb/sr, respectively. The reaction mechanism appears to be direct and excellent distorted-wave Born-approximation fits to the data yield a spectroscopic ratio of $\frac{S(0.727\mathrm{} \mathrm{MeV}, 2^{+})}{S(\mathrm{g}.\mathrm{s}.\mathrm{})}=0.64\mathrm{}\pm 0.13$ in good agreement with the value 0.61±0.24 derived from ${}_{}{}^{212}{}_{}{}^{}\mathrm{Po}$ $\alpha$ decay. Preliminary attempts at obtaining absolute α widths yield ${{\gamma }_{\alpha }}^2\left({}_{}{}^{212}{}_{}{}^{}\mathrm{Po}\right(\mathrm{g}.\mathrm{s}.\mathrm{}\left)\right)\sim 1.4$ keV from both $\alpha$ decay and the transfer reaction.

An apparent puzzle concerning the suppression of heavy-ion-induced $\mathrm{nn}$ and $\mathrm{pp}$ transfers compared to $\mathrm{np}$ transfer in light nuclei can be explained to a great extent by invoking simple arguments based on the binding energies of the transferred pairs to the two cores. The manifestation of this effect is in the tail regions of the appropriate bound-state wave functions where transfer is well known to occur. These arguments may be extended to include multinucleon transfers where the consequences of this effect could be even more drastic.

Remarkably large quasimolecular (molecular orbital) $K$-shell x-ray yields are found in 48-MeV S→ Ne encounters, unequivocally indicating that production of molecular-orbital x-rays can occur as a result of single-collision mechanisms. Gaseous and solid targets are found to give similar spectral shapes of the emitted continuum radiation.

It is proposed that amplified spontaneous emission in the soft-x-ray region can be obtained using inner-shell population inversions arising from the Auger effect. I treat ${\mathrm{Na}}^{+}$ and show that with present-day technology it appears possible to generate a pulse of ${10}^{-5\mathrm{}}$ to ${10}^{-7\mathrm{}}$ J in less than a nanosecond at 410 Å. The possible effect of interatomic Auger processes in the solid is discussed but high-electron-density effects are not accounted for.

The performance of ion-beam-irradiated fusion targets consisting of a high-density spherical shell containing DT gas has been calculated. Breakeven with 10-MeV protons irradiating 1-2-mm-diam targets can be produced with a beam current around 10 MA. Results for various target sizes and other beam particles and voltages are also discussed.

The relativistic Boltzmann equation with a Fokker-Planck collision term is solved assuming that elastic scattering characterizes the shortest time scale of the beam-plasma system. One-dimensional solutions containing the self-consistent return-current electric field show that, although range shortening occurs, the electric field prevents high-current-density beams from penetrating into the dense-plasma region.

It is shown that surface superconductivity can be used as a localized thermometer. Its application to the study of the thermal boundary resistance at a Pb-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ interface provides the first experimental evidence for the existence of a rapid temperature variation within microscopic distances from the surface.

Nine x-ray structure factors have been accurately measured in good-quality InSb single crystals and compared with various model calculations of the valence-electron charge distribution. Excellent agreement is obtained with a model based on tetrahedral distortion and ionic charge transfer, whereas Phillips's bond-charge model gave the poorest fit of all.

The dependence of photoelectron spin polarization on photon energy with ultrahigh-vacuum-cleaved surfaces of several ferrites shows that the electronic excitation spectrum of $3d$ states is described by the model of a single ion in a crystal field in all details. We obtain the relative intensity of the multiplet lines as well as the energy difference of $3d^{n-1\mathrm{}}$ final states on $A$- and $B$-lattice sites with high precision.

The $L_{2,3}$ excitation spectra of liquid and solid Na and Al were measured at several temperatures throughout the energy intervals 30-80 and 70-170 eV, respectively, using yield spectroscopy. The spike at the 31-eV Na edge is virtually unchanged in the liquid, indicating that the edge is insensitive to long-ranged crystalline order. The broader structures up to 100 eV above the edges in Na and Al, however, are washed out in the liquid.

The electronic structure of a jellium-Si interface is calculated with use of a jellium density corresponding to Al and self-consistent Si pseudopotentials. Local densities of states and charge densities are used to study states near the interface. The states which exist in the Si fundamental gap are bulklike in jellium and decay into Si with high concentration in the dangling-bond free-surface-like Si state. The calculated barrier height is in excellent agreement with experiment.

We present a three-dimensional band-structure calculation of ${\left(\mathrm{SN}\right)}_x$ using the empirical pseudopotential scheme. The density of states, Fermi surface, and optical spectrum are calculated. Estimates for the electron-phonon coupling constant $\lambda$ are given and the increase of $T_c$ with pressure is discussed. The assumption of an electron-phonon mechanism for superconductivity in ${\left(\mathrm{SN}\right)}_x$ is consistent with our results.

NMR and EPR measurements in V${\mathrm{O}}_2$ under uniaxial stress in the ${\mathrm{}\left[110\right]\mathrm{}}_R$ direction lead to a phase diagram entirely similar to that obtained in ${\mathrm{V}}_{1-x}{\mathrm{Cr}}_x{\mathrm{O}}_2$ alloys. Two intermediate phases $M_2$ and $T$ are observed, and, as established for ${\mathrm{V}}_{1-x}{\mathrm{Cr}}_x{\mathrm{O}}_2$, correspond to linear Heisenberg chains of spin ½ ($M_2$ phase) on one V sublattice. These chains undergo a progressive dimerization in the $T$ phase as the temperature is lowered.

We have found a strong temperature dependence in the dielectric constant of three different glasses below 5 K, which we ascribe to the low-energy excitations of the amorphous state. From our data we can determine the electrical dipole moment associated with these excitations, which gives rise to resonant absorption of electromagnetic waves. The corresponding absorption coefficient is expected to saturate at electromagnetic intensities above a few milliwatts per square centimeter.

A magnetite rod has been observed to rotate suddenly at up to six discrete temperatures between 110 and 183 K in a weak magnetic field (1.5 Oe).

A theory of the thermoelectric power associated with electronic phonon-assisted tunneling (hopping) motion between inequivalent sites has been developed. The general results have been applied to some prototype situations characteristic of hopping in disordered solids.

X-ray photoemission line shapes of $2s$ and $2p$ electrons from Al, Mg, and Na have been analyzed in terms of the theory of Mahan and of Nozières and De Dominicis. The resultant singularity indices, 0.115, 0.13, and 0.19, respectively, require that all x-ray threshold exponents, save that for the Na $K$ edge, be positive.

We report an experimental investigation of the lepton-nonconserving neutrinoless double $\beta$ decay of ${}_{}{}^{82}{}_{}{}^{}\mathrm{Se}$. The half-life of this decay mode is found to be greater than 3.1 × ${10}^{21}$ yr at a 68% confidence level. By use of the reported total lifetime of ${}_{}{}^{82}{}_{}{}^{}\mathrm{Se}$ obtained from recent mass-spectrometric measurements, an upper limit of 9% on the branching ratio for neutrinoless decay is estimated. This corresponds to an upper bound of ∼ 3 × ${10}^{-4\mathrm{}}$ for the lepton-nonconservation amplitude if a two-nucleon mechanism is assumed.

We present an exact solution to the nonlinear field equations which describe a classical excitation possessing magnetic and electric charge. This solution has finite energy and exhibits explicitly those properties which have previously been found by numerical analysis.

We have measured $p-d$ inelastic scattering at small momentum transfer by detecting the slow-recoil deuterons from a deuterium-gas-jet target. The coherent diffraction dissociation of protons on deuterons was studied in the region $0.03<\mathrm{}\left|t\right|<0.07\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$, $1.4<\mathrm{}{M_X}^2<4\mathrm{}$ Ge${\mathrm{V}}^2$, and for energies from 50 to 275 GeV. In this region, the diffractive cross section exhibits structure and is dominated by an enhancement at ${M_X}^2\sim 1.9$ Ge${\mathrm{V}}^2$.