The $Q$-value dependence of the cross section for few-nucleon transfer in the reaction ${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}({}_{}{}^{16}{}_{}{}^{}\mathrm{O}, X)$, $X$ being ${}_{}{}^{16}{}_{}{}^{}\mathrm{N}$, ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, or ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$, at an ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ bombarding energy near the Coulomb barrier, is obtained from a simple model in which the population of states in the residual nucleus is determined to be of maximum entropy, subject to the one constraint that the mean value of the $Q$-value spectrum is the observed mean value.

Total cross sections for charge transfer in ${\mathrm{Mg}}^{+}$-Mg and ${\mathrm{Mg}}^{++}$-Mg collisions have been measured in the energy range of 1.2-1000 keV. The cross section for resonant double-charge transfer shows a pronounced structure which can be understood as an effect of phase interference between two resonant charge-transfer channels. This is substantiated quantitatively by a model calculation.

The effect of the polarization of the vacuum in magnetic fields not too far below $B_c=\frac{{m_e}^2{c}^3}{e\hslash }=4.4\mathrm{}\times {10}^{13}$ G on the polarization and transport of the radiation in plasma is discussed, and found to be significant. The expressions for the cross sections of all radiative processes are altered thereby. We present a calculation of the Thomson cross section, in which inclusion of vacuum effects leads to well-marked departures from previously computed behavior. These effects should lead to possible observable consequences in pulsars.

Numerical simulation of magnetic reconnection with $O$-type magnetic island has shown that as reconnection develops the plasma flow pattern suddenly changes from the tearingmode type to a pattern such that the plasma is accelerated along the boundary layer of the magnetic island and is confined inside the island. The pressure of the island is accordingly drastically increased and the island swells and expands. Comparison with the open-ended ($X$-type) reconnection process has shown that "fireballs" in the magnetosphere can well be accounted for.

A potentially distruptive new phenomenon in imploding targets is described. Initially weak standing sound waves (vibrations) in an imploding spherical shell can become comparable in amplitude with the shell thickness if the effective adiabatic index satisfies $\gamma <{\gamma }^{*}$, where ${\gamma }^{*}$ depends on how the aspect-ratio changes during compression. Detailed calculations for a model of self-similar implosions with ${\gamma }^{*}=\frac{5}{3}$, show that the relative amplification is strongest for long-wavelength modes in thin shells with small $\gamma$, and is insensitive to the density profile.

The presence of ${\mathrm{Fe}}^{2+}$ ions in tetrahedral sites of iron garnets has been detected for the first time. The particular material in which this occurred was flux-grown Nb-doped yttrium iron garnet. Proof of occupancy of tetrahedral sites by ${\mathrm{Fe}}^{2+}$ ions was obtained by Tucciarone's recently developed method of the angular variation of induced anisotropy.

Depolarization of ${\mu }^{+}$ particles implanted into quenched alloys of 0.042, 0.13, and 0.42 at.% Cu in Al shows peaks in the temperature dependence which are attributed to trapping of the muons by various metastable Cu impurity complexes, and provides evidence that positive muons can be used to study impurity correlations in metals.

Despite the fact that the Frenkel-Kontorova model, with chain of atoms and sinusoidal potential incommensurate, lacks translational symmetry, the structure factor $S(q, \omega )$ for this model is shown to exhibit always phonon peaks of negligible width.

Modulations of up to a factor of 2 were observed in the Se $3d$ photoelectron intensity normal to the surface, for selenium overlayers on Ni(100), as the photon energy was varied from 90 to 240 eV. Excellent agreement of peak energies with predictions by Tong and Li was obtained for both the $c(2\mathrm{}\times 2)$ and $p(2\mathrm{}\times 2)$ structures, using the hollow-site geometry. Normal photoelectron diffraction appears to have promise as a surface structural method.

To describe the metal-insulator transition in doped semiconductors, we have worked out a model which incorporates electron-electron interactions through the Kohn-Sham density-functional scheme within the cellular approximation. The vanishing of the conductivity activation energy, the impurity-band formation, and the change from spin-polarized localized states to unpolarized extended ones are accounted for. We predict these states to coexist in a narrow temperature and concentration range.

Antiferromagnetic structures of nuclear spins of ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ and ${}_{}{}^1{}_{}{}^{}\mathrm{H}$ have been produced in a single crystal of lithium hydride by the now standard method of dynamic nuclear polarization followed by an adiabatic demagnetization in the rotating frame (ADRF). The (110) Bragg reflection, characteristic of an antiferromagnetic superstructure, has been observed by neutron diffraction. Its line shape and linewidth have been measured, and the sublattice polarizations studied as a function of variables related to the energy and the entropy of the nuclear spins.

The angular distribution of neutrinos and antineutrinos emitted by a rotating black hole is asymmetric. More antineutrinos are emitted in the direction parallel to the hole's angular momentum; more neutrinos in the antiparallel direction. This result applies not only to black holes, but to any rotating star emitting thermal neutrinos. Emission of other particles can also be asymmetric as a result of parity-nonconserving weak interactions.

Using a molecular-dynamics technique, we studied some nonequilibrium properties of the sine-Gordon chain in one space dimension. We found a $t^{\frac{4}{3}}$ long-time tail in the mean-square displacement, and self-diffusion is traced back to the motion of kink solitons. It is shown that the propagation of these kinks gives rise to a new excitation branch.

This paper presents results of an experiment on hadron production in deep-inelastic electron scattering. Good agreement with the predictions of the quark-parton model is found. The Fragmentation functions for $u$ and $d$ quarks into pions are determined, and comparison is made with other deep-inelastic processes and with recent quark jet parametrizations.

We have measured the spin-spin correlation parameter $C_{\mathrm{LL}}=(L, L;0, 0)$ in $p-p$ elastic scattering around ${\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}=90\mathrm{}°$ from $p_{\mathrm{lab}}=1.0\mathrm{} \mathrm{to} 3.0$ GeV/c. We observe a rapid energy dependence in $C_{\mathrm{LL}}$ and describe our interpretation of the results.

The implications of pure vector-type quark-quark interaction for the spin correlation parameters of large-angle elastic nucleon-nucleon scattering are discussed on the basis of a quark elastic-scattering model. The significance of spin-correlation measurements for the understanding of the nature of the quarks is also discussed.

It is shown that the rotational signatures for ground-band $\alpha$ decay can be calculated from nuclear ${\beta }_2$ and ${\beta }_4$ deformation values. The $\alpha$-decay probability function over the nuclear surface is equated with the differences of the parent and daughter surfaces, hence with the changes in deformation parameters. It is suggested that deformation values can be used to infer $\alpha$ wave functions at the nuclear surface for $\alpha$-transfer reaction theory on rotational signatures.

The neglect of $n$-body breakup contributions, $n>~3$, is a widely used but previously untested approximation occurring in the analysis of almost all atomic, molecular, and nuclear collisions. A simple three-body model of deuteron stripping is used to study this approximation. Below the breakup threshold, use of this approximation accounts for the overall shape of the angular distributions and fits the exact transfer cross section at forward angles. With increasing energies, continuum effects render this approximation much less accurate.

I demonstrate that a two-fireball model can explain the proton and pion inclusive spectra for collision between light ions at relativistic energies. For havier ions, the one-fireball model is recovered.

We show that accurate high-momentum-transfer electron-scattering data now being obtained can provide essential constraints on analyses of nuclear structure. However, the usefulness of these data is seriously impaired if meson-exchange current effects are ignored.