The spin polarization of a single magnetic impurity in a metal in an external magnetic field has been calculated by variational method. The results are in agreement with the measurement of the hyperfine field by the Mössbauer technique.

The lifetimes and polarizations of intrinsic recombination radiation from alkali-halide crystals at low temperature are interpreted in terms of two self-trapped exciton states, one predominantly singlet, the other triplet in character. This is the first strong evidence for the triplet assignment. The variation with crystal of the triplet-state lifetime is attributed to effects of the different halogen spin-orbit couplings and the varying degrees of axial relaxation in the self-trapped configuration.

The de Haas-van Alphen effect has been studies in spherically shaped crystals of nickel. The unusual angular variations in the frequencies arising from the $X_5$ hole pockets can be accounted for in terms of an interpolation scheme which includes the effect of spin-orbit coupling. The sizes of the hole pockets depend markedly on the axis of spin quantization, i.e., on the direction of the applied magnetic field.

An apparently good fit of the summed transverse and longitudinal form factors to the total measured form factor for inelastic electron scattering to the 19-MeV levels of ${\mathrm{C}}^{12}$ appears less good when the two components are distinguished. Evidence for the $T=1\mathrm{}$, $J=1^{-}$ and $T=1\mathrm{}$, $J=2^{-}$ states seems clearly established, but the longitudinal form factor indicates that another level is contributing.

Cross sections and angular distributions for the quasi-two-body final states $N^{*++}{\rho }^0$, $N^{*++}{\omega }^0$, and $N^{*++}{\eta }^0$ were measured at five incident ${\pi }^{+}$ momenta between 3 and 4 GeV/c. These cross sections, when combined with results at higher momenta, indicate that the momentum dependence of the $N^{*++}{\rho }^0$ cross section deviates from that expected for a meson-exchange reaction, and that there is shrinking of the diffraction peak. Dips in the production angular distributions are observed, similar to those observed in two-body final states.

The time distribution of 335 leptonic decays of $K^0\text{'}\mathrm{s}$ produced by $K^{+}+d\to K^0+p+p$ has been analyzed. The likelihood estimate for $x{e}^{i\varphi }$, the ratio between the $\Delta S=\Delta Q$ violating and nonviolating amplitudes, yields $x={0.26}_{-0.11\mathrm{}}^{+0.08\mathrm{}}$ and a phase $\varphi ={50°}_{-27\mathrm{}°}^{+25\mathrm{}°}$.

We have studied $K^{+}p$ elastic scattering near the backward direction at a beam momentum of 3.5 GeV/c. In addition to providing evidence for baryon exchange, the experimental results show a possible turnover of the angular distribution for positive values of $u$ which is interpreted in terms of a Reggeized baryon exchange model. We have made a comparison of $K^{+}p$, ${\pi }^{+}p$, and ${\pi }^{-}p$ backward scattering within the framework of SU(3) which leads to predictions concerning other, as yet unmeasured, $K^{+}N$ processes.

We have studied $K^{+}p$ elastic scattering near the backward direction at a beam momentum of 3.5 GeV/c. In addition to providing evidence for baryon exchange, the experimental results show a possible turnover of the angular distribution for positive values of $u$ which is interpreted in terms of a Reggeized baryon exchange model. We have made a comparison of $K^{+}p$, ${\pi }^{+}p$, and ${\pi }^{-}p$ backward scattering within the framework of SU(3) which leads to predictions concerning other, as yet unmeasured, $K^{+}N$ processes.

Small structures observed in $K^{-}p$ and $K^{-}d$ total-cross-section measurements are interpreted as indications for two new $I=1\mathrm{}$ resonances at c.m. energies of 2455±10 and 2595±10 MeV.

This paper reports the results of x-ray spectrum and location measurements of several cosmic x-ray sources made on 18 May 1967. Rocket-borne proportional counters were used. The x-ray spectra of Sco XR-1, Tau XR-1, and Lup XR-1 were measured, and the location of Vel XR-1, Lup XR-1, and a new source Cen XR-3 were determined. In addition, the x-ray spectrum and location of a variable source, Cen XR-2, were obtained.

Experimental optical third-harmonic coefficients for inert gases are presented and compared with experimental Kerr coefficients and theoretical dc hyperpolarizabilities.

A fluctuation theory of the intrinsic critical velocity of a superfluid near the lambda point is developed in analogy with the droplet model of condensation of a supersaturated vapor. For the superfluid, vortex rings play the role of critical droplets in homogeneously nucleating transitions to states of lower superflow. A quantitative estimate is in reasonable agreement with recent experiments on helium.

The vanishing of the quasiaverages usually associated with superfluidity and superconductivity is shown for arbitrarily interacting Bose and Fermi systems which are confined to a geometry with one or more dimensions finite while one or more dimensions extend to infinity. However, it is suggested that these partially finite geometries are anomalous and are not good approximations to thin film and pore geometries found in the laboratory. The conditions on the box size which are necessary and sufficient for condensation to occur in an ideal Bose gas are also given.

For the case of a charged impurity atom in an unpolar crystal, a sum rule is derived for the "apparent charges" in terms of the photoelastic constants of the pure material. From this, the polarization due to short-range interactions between the impurity and its neighbors can be estimated. This is of importance for the absorption by the vibrations of these neighbors.