Evaporation-residue cross sections, $A$ and $Z$ distributions, and $\gamma$-ray multiplicities are reported for ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ and ${}_{}{}^{86}{}_{}{}^{}\mathrm{Kr}$ reactions leading to various Er compound nuclei. When combined with previous data the results show an angular momentum limit approximately consistent with the expected onset of fission modified by contributions from charged-particle emission. No evidence is found for an absence of evaporation residues from low-$l$ collisions in the ${}_{}{}^{86}{}_{}{}^{}\mathrm{Kr}$ cases.

The circular polarization of muonic x rays has been measured in order to investigate the mechanism of the unexpectedly fast depolarization of the negative muon in Pd metal as observed by the negative-muon spin-rotation method. A large circular polarization consistent with the maximal theoretical value was observed in both Pd and Cd metals, showing that the polarization is preserved up to the time the muon reaches the $1s$ atomic ground state.

A general technique is presented in which narrow non-Lorentzian laser-induced resonances are used to study molecular reorientation. The experiments, which study the ${\nu }_{2}asQ(8, 7)$ N${\mathrm{H}}_3$ transition, yield a value of 6 ± 1 MHz/Torr for the excited-state alignment relaxation rate, 50% larger than the corresponding population relaxation rate.

A time-delayed technique is used to study the decay of narrow laser saturation resonances induced in the ${\nu }_{2}asQ(8, 7)$ transition of N${\mathrm{H}}_3$. The experiments dramatically separate the distinct contributions to the line shape due to population saturation and Ramantype processes, and yield a value of 3.5±0.6 MHz/Torr for the excited-state population decay rate.

We report the first measurements of Doppler-free two-photon linewidths obtained with a simple coherent transient technique using a wide-bandwidth laser. Measurements of two-photon optical-free-induction decay are used to determine pressure-broadening coefficients for the $3S-4D$ transition of sodium for collision with helium, neon, and argon. Pressure-broadened linewidths of several tens of MHz are measured with laser linewidths of several GHz.

Computer simulation of neutral injection into a mirror machine shows the existence of stable two-dimensional ($\mathcal{r}, z$) field-reversed mirror configurations. The code follows ion orbits in self-consistent magnetic fields; all electron currents have been ignored. For small systems only a few gyroradii in extent, it is only necessary to focus the neutral beam off axis. Stability to the Alfvén ion cyclotron mode is due in part to finite-length effects. Some steady states for large systems have also been observed.

Specific heat $C_p$ and thermal conductivity $\kappa$ measurements between 0.1 and 10 K on the superconducting ($T_c=2.53\mathrm{}$ K) and structurally disordered metal ${\mathrm{Zr}}_{0.7}$${\mathrm{Pd}}_{0.3}$ exhibit an approximately linear term in $C_p$ and a $T^{1.9}$ dependence of $\kappa$ below $T_c$. The magnitudes of these terms are close to those found for insulating glasses, thereby suggesting that disorder-induced localized excitations exist at similar densities in very different classes of disordered solids.

This paper reports elastic and inelastic neutron-scattering studies on the incommensurate linear-chain mercury compound ${\mathrm{Hg}}_{3-\delta }\mathrm{As}{\mathrm{F}}_6$. The one-dimensional phonon dispersion curve associated with the randomly phased linear Hg chains has been measured at room temperature. A transition, at 120 K, from a randomly phased interchain structure to a "phase-ordered" structure has been found and characterized.

Theoretical studies of the bonding of atomic H to the Si(100) surface indicates that a strong but unconventional covalent bond can be formed between the H and a Si atom in the second layer whose conventional tetrahedral bonds are already saturated.

We report an investigation of the direct forbidden absorption edge of Ti${\mathrm{O}}_2$. For the first time we have resolved the weak quadrupolar $1s$ exciton and measured its binding energy. Taking into account polaron effects, we estimated the bare electron effective mass in the ${\Gamma }_1$ minimum of the conduction band and obtained a fairly reasonable value of $3m_0$.

Nuclear-spin Zeeman states prepared at a low temperature in the rotating frame were matched to the torsional ground-state splittings of N${\mathrm{H}}_4$ and C${\mathrm{H}}_3$ groups in solid lattices at a higher temperature. A resonant transfer of order was observed to occur instantaneously. Measurements yield a part of the torsional spectrum and the torsional relaxation time. From the torsional relaxation, the torsional lifetime broadening of a N${\mathrm{H}}_4$ ground state in ammonium iodide at 10 K was found to be ∼ 1 Hz.

The production of gravitons in a homogeneous, isotropic, spatially flat universe containing radiation and a small admixture of cold baryons is studied by an effective-potential method which takes into account the back reaction of the produced gravitons on the geometry. The total probability per unit volume to produce a pair of gravitons is finite and has a very small value for a universe with parameters corresponding to my own.

Vibrational-dephasing times have been measured in mixtures of liquid ${\mathrm{N}}_2$ and Ar. The correlation time of the molecular motion initiating the dephasing process is calculated to be 2.2 and 4.6 ps in pure ${\mathrm{N}}_2$ and pure Ar, respectively. These rather long correlation times suggest that the dephasing results from the average force field determined by the number of nearest-neighbor molecules.

We formulate the problem of colliding plane gravitational waves with two polarizations as the harmonic mappings of Riemannian manifolds and construct an exact solution of the vacuum Einstein field equations describing the interaction of colliding impulsive gravitational waves which in the limit of collinear polarization reduces to the solution of Khan and Penrose.

Using the molecular-dynamics technique, we establish solitonlike properties of heat pulses in a lattice-dynamic model when the ambient temperature is in the second-sound regime.

The anomalous neutrinoless conversion of stopped negative mouns into electrons has been searched for in sulfur. No electron with an energy above 93 MeV was found. The upper limit for the branching ratio relative to ordinary muon capture is 4×${10}^{-10\mathrm{}}$ at the 90% confidence level.

The quark structure functions of the proton are determined through a combined analysis of the reactions $\mathrm{pN}\to l\overline{l}X$ and $\mathrm{eN}\to \mathrm{eX}$. The valence-quark structure function of the pion is also given by analyzing the $\pi N\to \mu \overline{\mu }X$ data measured by the Branson et al.

The weak parity-nonconserving asymmetry in the total cross section for the scattering of longitudinally polarized neutrons from deuterons at 14.4 MeV is estimated using strong $n-d$ scattering amplitudes from an $s$-wave, separable-potential Faddeev calculation. The weak force is parametrized in terms of $\rho$, $\omega$, and $\pi$ exchange and treated perturbatively. We find that $A_{\mathrm{nd}}=0.8\mathrm{}\times {10}^{-7\mathrm{}}$ when $A_{\mathrm{pp}}=2.6\mathrm{}\times {10}^{-7\mathrm{}}$.

An "island" of isomeric states with high multiplicities found in a recent experiment are interpreted as "yrast traps" in deformed nuclei rotating around a symmetry axis. According to our interpretation, a group of trap states for neutron numbers around 82 and angular momenta below 40 is connected with the nuclear shell structure for weakly deformed potentials. A second group of traps situated in a more narrow region around neutron number 82 and with angular momentum around 50 is attributed to the occurence of shell structure for a ratio of axes 2: 3.

Recently published data for the stopping power of fully stripped channeled ions are interpreted in terms of the Vavilov theory of energy straggling. The qualitative dependence of $\frac{{\left(\frac{\mathrm{dE}}{\mathrm{dx}}\right)}_p}{{Z_1}^2}$ on charge and velocity can be explained by the dependence of the asymmetry of the energy-loss probability density on these variables through the parameter $\frac{\xi }{{\epsilon }_{max}}$.