Microscopic calculations of noble-gas adsorption on metals which include the effect of metallic nonlocal dielectric response are presented for two models of electronic boundary conditions at the metal surface. Spatial dispersion causes the Van der Waals interaction to decrease slower than the conventional $d^{-3\mathrm{}}$ law indicates. Systematics of the physisorption indicate that interaction energies, but not equilibrium positions, are very sensitive to nonlocality. The results are relatively insensitive to to the details of the electronic boundary conditions.

A large $q$-direction dependence of the broad band close to the TO peak is observed and explained qualitatively and quantitatively. The TO peak is found to be repelled out of a two-phonon band by a strong third-order anharmonic interaction.

Acoustic-paramagnetic-resonance and electric-field-induced thermally detected EPR measurements have been made in crystals of ${\mathrm{Al}}_2$${\mathrm{O}}_3$: ${\mathrm{Ni}}^{3+}$. To reconcile theory with experiment, dynamic Jahn-Teller effects must be present, and, in addition, $2q-p$ is shown to be less than unity. This is the first reported example of an orbital doublet for which the multimode rather than the cluster model is needed.

Distinct "chemical effects" were observed among high-resolution, nonderivative, nitrogen $K-LL$ Auger-electron distributions from chemisorbed N${\mathrm{H}}_3$ on molybdenum surfaces and gaseous N${\mathrm{H}}_3$, which depend on the electronic structures of the adsorbed species. A calculation in the semiempirical "equivalent-core approximation," based on photoelectron data, revealed the origins of the fine structure in the observed Auger spectra. It is concluded that N${\mathrm{H}}_3$ is chemisorbed as a ${\mathrm{H}}_{-\mathrm{Mo}}--{\mathrm{N}}_{-\mathrm{Mo}}{\mathrm{H}}_{x<~2}$ dissociative configuration at about room temperature and the surface nitride is formed at 450°C.

We demonstrate the use of phosphorescence microwave double resonance (PMDR) in ionic solids applied to the dynamic Jahn-Teller effect in $F$ centers of CaO. A tunnel splitting ($\Delta =2.1\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$) is obtained and Jahn-Teller states are coherent in zero field at least ${10}^3$ times longer than the stochastic limit, and possibly as long as the lifetime of the centers. This is demonstrated by showing the loss of coherence by small Zeeman perturbations on the PMDR spectrum.

We give an approximate renormalization-group formulation which parallels that of Wilson. The group generator represents the momentum-independent limit of the differential generator of Wegner and Houghton. The eigenfunctions near the Gaussian point are computed for all spin dimensions $n$ and lattice dimensions $d$, including $d=2\mathrm{}$. The nontrivial fixed-point Hamiltonian in dimensions near $d=\frac{2\mathcal{O}}{(\mathcal{O}-1)}$, together with the eigenvalues near that nontrivial fixed point, are found explicitly to first order in ${\epsilon }_{\mathcal{O}}\equiv \mathcal{O}\mathrm{}(2-d)+d$ for all values of $n$ and the order $\mathcal{O}$. Odd-dominated Ising systems and corresponding expansions in ${\epsilon }_{\mathcal{O}-\frac{1}{2}}$ are also treated.

Cases are found in which the Strutinsky prescription for single-particle corrections to the liquid-drop model fails. Estimates of the spontaneous-fission lifetimes of super-heavy elements are found to be overly sensitive to small changes in the assumed single-particle level spectrum.

It has been proposed that the Bondi-Metzner-Sachs group affords a possible explanation for the discreteness of elementary-particle spins. This discreteness result depends on the topology given to the group. A careful analysis of representations in the "nuclear" topology indicates that discrete-spin representations (those subsumed by the original topology) describe bound gravitating systems ("elementary particles") whereas the new continuous-spin representations, if physically realistic, describe scattering states of gravitating systems.

We have measured deep inelastic muon-deuteron scattering in the range $0.4<\mathrm{}{Q}^2<3.4\mathrm{}$ and $1.6<\mathrm{}\nu <5.6\mathrm{}$ GeV. We have extracted the neutron structure function and find that $\nu {W_2}^n$ differs significantly from $\nu {W_2}^p$, as also found in $e-d$ scattering. To compare $\mu -d$ and $e-d$ scattering we form the ratio $\mathcal{r}\left(Q^2\right)=\frac{{{\left(\nu W_2\right)}_{\mu }}^d}{{{\left(\nu W_2\right)}_e}^d}=N{(1+\frac{Q^2}{{\Lambda }^2})}^{-2\mathrm{}}$ and find $N=0.925\mathrm{}\pm 0.038$ and $\frac{1}{{\Lambda }^2}=-0.019\mathrm{}\pm 0.016$.

We have measured the ratio $\frac{\Gamma ({K_L}^0\to {\pi }^{+}{\pi }^{-}\gamma )}{\Gamma ({K_L}^0\to \mathrm{all})}$ to be (6.2 ± 2.1) × ${10}^{-5\mathrm{}}$. The rate and Dalitz-plot distribution are consistent with $\mathrm{CP}$ conservation in this weak-electromagnetic decay.

The qualitative consequences of Hawking's prediction of thermal emission from black holes are considered. Whereas mass and angular momentum loss proceeds on cosmologically long time scales, on the other hand electric discharge will take place extremely rapidly. Hypothetical mechanisms for baryon and lepton conservation are discussed.

The quantity $R=\frac{{\sigma }_L}{{\sigma }_T}$ is extracted for the proton, deuteron, and neutron from deep inelastic $e-p$ and $e-d$ scattering cross sections measured in recent experiments at Stanford Linear Accelerator Center. For $\omega <~5$ the kinematic behavior of $\nu R_p$ is consistent with scaling, indicative of spin-½ constituents in a parton model of the proton. We also find that within large statistical errors, $R_d$ and $R_n$ are consistent with being equal to $R_p$.

The differential-cross-section ratios have been measured for excitation of the $n=2\mathrm{}$ and $n=1\mathrm{}$ ${\mathrm{He}}^{+}$ states in the electron-impact ionization of helium using the coplanar symmetric geometry. This reaction is a crucial test of the reaction model and of the helium wave function. The experiment is sensitive enough to rule out the Hartree-Fock function. Excellent agreement is obtained by using a configuration-interaction wave function.

Measurements are reported on the densities and isotopic-abundance ratios of nearly perfect Si single crystals. These, when combined with optical interferometry of the crystal repeat distance, yield a new value for the Avogadro constant. This result, $N_A=6.022\mathrm{}0943\times {10}^{23}$ ${\mathrm{mol}}^{-1\mathrm{}}$ (1.05 ppm), represents a more than thirty-fold reduction in the uncertainty of previous direct measurements.

In its diagrammatic form the perturbation expansion for the dispersion interaction can be rearranged to an expansion in the degree of hyperpolarizability considered. The total contribution of the linear dipole polarizabilities is given explicitly.

The mechanisms of spontaneous and induced emission of radiation are derived from the Dirac equation in a rotating coordinate system. The molecular-orbital x-ray spectra exhibit a strong asymmetry with respect to the beam axis. The asymmetry peaks for the high-energy transitions, which can be used for spectroscopy of two-center orbitals.

We have observed an anisotropic angular distribution for the high-energy continuum x rays emitted in high-energy collisions of Ni ions with Ni atoms. The variation of the anisotropy with photon energy is uniquely characteristic of induced radiative transitions in quasimolecules, and hence provides strong evidence for the quasimolecular origin of these radiations.

The x-ray emission for 6- to 60-MeV iodine bombardment on thin Au targets was measured. Spectra, cross sections, and angular dependence of x-ray emission are reported. Special emphasis is placed on the noncharacteristic radiation formerly interpreted as $M$ radiation of a quasiatom with an effective atomic number of 132. The emission of this radiation is found to be nonisotropic strongly supporting the model of induced emission in the collision molecule.

${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}_{}^{+}{}_{}{}^{}\left(3\mathrm{}{d}^{6}4s\right)$ ions have been produced by uv irradiation of a xenon matrix containing 0.65% ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$. The stabilization of these ions was accomplished by mixing ∼1% of HI into the Xe matrix gas. The Mössbauer isomer shift of the ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}_{}^{+}{}_{}{}^{}\left(3\mathrm{}{d}^{6}4s\right)$ resonance is + 0.26 ± 0.03 mm/sec against iron metal at 300 K. From this we obtain the ratio of the electron densities at the ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$ nucleus, $\frac{[\rho {\mathrm{}\left(0\right)\mathrm{}}_{3d^{6}4s^2}-\rho {\mathrm{}\left(0\right)\mathrm{}}_{3d^6}]}{[\rho {\mathrm{}\left(0\right)\mathrm{}}_{3d^{6}4s}-\rho {\mathrm{}\left(0\right)\mathrm{}}_{3d^6}]}=1.80\mathrm{}\pm 0.15$.

Scattering intensity and related measurements have established the tricritical exponents for the divergences of the concentration susceptibility, $\gamma$, and of the correlation length for concentration fluctuations, $\nu$, have indicated a probable value for the exponent $\eta$, and have established a region of tricritical scaling.