Linear momentum transfers have been determined for ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$-induced reactions at energies from 30 to 84 MeV/u on U, Au, and Ni. The folding-angle distribution of the fission fragments for the first two targets, and the angular distribution of low-energy protons emitted by the nickel-like nucleus, provide evidence for a limitation of the transferred momentum at 2 GeV/c. This limitation effect is reached above a bombarding energy around 15 MeV/u.

Gamma decay of the low-energy octupole resonance in ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$ was studied by inelastic $\alpha$ scattering at 99.3 MeV. Correlation functions measured for the ground-state transition support a spin-3 assignment for the low-energy octupole resonance. Observed branching ratios to the ground and the low-lying states around $E_x\sim 2.2$ MeV are respectively (7.9±1.0)% and (32±10)%, which are significantly larger than those predicted by the statistical-decay model.

It is shown that, for heavy-ion projectiles with a cluster structure, effects due to projectile excitation generate a large effective spin-orbit interaction which can drastically alter the predictions for vector analyzing powers obtained from folding model spin-orbit potentials. Coupled-channels calculations of this effect for ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ and ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ scattering from ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}\sim 20$ MeV give a good account of experimental data.

This paper presents the results of an analytic calculation of the corrections of relative order ${\alpha }^2\left(\frac{m_e}{m_{\mu }}\right)$ to the muonium ground-state hyperfine splitting due to exchanged photons. Theory and experiment are compared, with these corrections and some radiative-recoil contributions described in an accompanying paper taken into account.

This paper presents the results of an analytic calculation of radiative corrections to the leading recoil corrections in the muonium ground-state hyperfine splitting. The principal new results are of relative order ${\left(\frac{\alpha }{\pi }\right)}^2\left(\frac{m_e}{m_{\mu }}\right)\ln \left(\frac{m_{\mu }}{m_e}\right)$. Also presented is an estimate of the contribution of the hadronic term in the vacuum polarization. A contribution to the positronium ground-state hyperfine splitting of relative order ${\left(\frac{\alpha }{\pi }\right)}^2$, arising from vacuum polarization of exchanged photons, is also given.

The triply differential cross section for the single ionization of helium by 500-eV electrons has been measured in a coplanar asymmetric geometry and analyzed by using a second Born-approximation treatment. It is found that these theoretical predictions concerning the angular positions, shapes, and magnitudes of both the binary and recoil peaks are in good agreement with experiment.

A complete kinematic analysis of photoelectrons from polarized targets with total angular momentum $J=\frac{1}{2}$ is given for the first time. Several simple experiments are suggested to test correlation and relativistic effects in atoms or molecules.

Singly, doubly, triply, and quadruply charged krypton ions are formed by multiphoton absorption processes in krypton atoms. They are induced by a 50-psec laser pulse at 1.064 μm in the ${10}^{13}$-${10}^{14}$-W-${\mathrm{cm}}^{-2\mathrm{}}$ intensity range. The percentage ratio between the numbers of doubly and singly ionized Kr atoms is 10% at 8×${10}^{13}$ W ${\mathrm{cm}}^{-2\mathrm{}}$. It is shown that ${\mathrm{Kr}}^{2+}$ ions result from a direct 33-photon absorption process. At 1.5×${10}^{13}$ W ${\mathrm{cm}}^{-2\mathrm{}}$, the 33-photon absorption rate is only about 60 times less than the 13-photon absorption rate which gives singly charged ions.

Recent experiments at strain rates reaching 0.1 GHz suggest a power-law dependence of solid-phase shear stress on strain rate. Novel nonequilibrium molecular dynamics simulations of plastic flow have been carried out. These steady-state isothermal calculations appear to be consistent with the present-day experimental data and suggest that the flows of metals can be described by a single physical mechanism over a range of strain rates from 10 kHz to 1 THz.

A novel toroidal plasma device has been tested in which the plasma is confined in a surfacelike multipole cusp field generated by permanent magnets. A toroidal current, driven by an induced electric field, is preferentially carried by the ions which are directly Ohmically heated ($T_i>T_e$). Plasma $\beta \text{'}\mathrm{s}$ of 20%-30% have been observed. Computer simulations verify a simple model of device operation.

A method for driving current in a fusion-producing plasma is proposed. Radio-frequency power is used to prohibit fusion-produced energetic particles from slowing down isotropically or to push them in a preferential direction. As a result, a net plasma current is generated whose efficiency is comparable to other current drive schemes.

The power spectrum of plasma density fluctuations in the range of frequencies of drift waves has been investigated in the Princeton Large Torus tokamak. The results suggest that the observed fluctuations evolve to a strong nonlinear state, and therefore they emphasize the need for a complete nonlinear theory of drift waves in tokamaks to assess their effects on plasma transport.

The first measurements are reported showing that the thermal boundary resistance between a metal and liquid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ depends on the applied magnetic field. The resistance, which is not affected by pressure changes or superfluidity of the liquid, is insensitive to fields less than 2 kG, but increases by a factor of 3 when the field is increased to 8 kG. The experimental results are explained by a model which assumes that the thermal transfer between the Pt and ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ is due to a magnetic coupling between the magnetic moments of conduction electrons in the metal and the nuclear spins of the solid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ layer on the Pt surface.

The first acceleration measurements are reported for negative ions in bulk superfluid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$. Data recorded at 70 mK, 25 bars for electric fields in the range $80<E<\mathrm{}150\mathrm{}$ V ${\mathrm{m}}^{-1\mathrm{}}$ are consistent with an ionic dispersion relation identical to that of a free particle with mass $(87\mathrm{}\pm 5)m_4$, where $m_4$ is the ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ atomic mass.

Experiments on rotating superfluid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-$A$ in an open cylindrical geometry show a change in the NMR line shape as a result of rotation: The amplitude of the peak decreases in proportion to $f\left(T\right)g\left(\Omega \right)$, where $\Omega$ is the angular velocity of rotation; at the same time the line broadens. Near $T_c$, $f\left(T\right)\mathrm{}$ is a linear function of $1-\frac{T}{T_c}$. At small velocities $g\left(\Omega \right)\propto \Omega$. These observations are consistent with the existence of vortices in rotating ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-$A$.

The superleak sound transducer is investigated theoretically. It is concluded that first sound is virtually never excited and that the characteristically low driving efficiency of second sound is caused by diffusion across the pores. Suggestions are provided on how to enhance the driving efficiency by several orders of magnitude. In ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-$A_1$, the signal strength is related to the magnetic properties of the diaphragm surface, opening new areas of application.

A scheme is presented for deriving atomic force constants that is fairly accurate, yet simple enough to allow determination of the dynamical matrix of bulk solids, relaxed and reconstructed surfaces, defects, etc. For illustrative purposes, the method is applied to bulk SiC to predict the phonon dispersion curves throughout the entire Brillouin zone, and to a carbon vacancy in SiC to study the change of atomic force constants due to atomic relaxations.

The ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$ Mössbauer effect on 16.8-at.% Fe-Au displays the magnetic double transition from paramagnetism to ferromagnetism at $T_c=165\mathrm{}$ and from ferromagnetism to spinglass-like behavior at $T_f\sim 45$ K. Below $T_f$ the magnetic state is characterized by freezing of Fe spin components which are transverse with respect to a strong applied dc field.

It is shown that quasiparticle scattering by a defect in a superconductor leads to large elementary pinning energies of flux lines. In the case of a small radius ($R$) point defect the new mechanism outweighs the traditional volume effect by the factor $\frac{{\xi }_0}{R}$.

This paper reports calculation of the time-correlation function of an electron wave of given wave vector $k$ in a three-dimensional medium with weak scatterers randomly distributed. An initial parabolic decay is followed by the usual exponential law which, asymptotically, gives way to a $\frac{1}{t^3}$ law.