We have measured the real part of the surface impedance $R\left(H\right)\mathrm{}$ of potassium at 1.2°K in a magnetic field normal to the sample surface. We find a sharp peak in $R\left(H\right)\mathrm{}$ at the value of $H$ where Cheng, Clarke, and Mermin predicted a new correlation-produced magnetoplasma mode should exist. We interpret the peak in $R\left(H\right)\mathrm{}$ as confirmation of the existence of the mode, and we ascribe to surface roughness the overall variation in $R\left(H\right)\mathrm{}$.

The fluorescence efficiency of tetracene single crystals may be enhanced by as much as 38% in a magnetic field $H>\mathrm{}2000\mathrm{}$ G. The enhancement is anisotropic with respect to the orientation of $H$ in the $\mathrm{ab}$ plane. It is shown that a magnetically sensitive coupling of singlet states to a double-triplet-exciton state ($T_1{T}_1$) at ∼2.40 eV is an important channel for radiationless decay in crystalline tetracene above 160°K.

Measurements of the temperature dependence of the yield stress in tungsten crystals show a temperature-independent region, which is consistent with Gilman's theory of quantum mechanical tunneling of dislocations.

We have found that photoelectrons from ferromagnetic gadolinium show spin polarization, the preferential direction of the magnetic moment being parallel to the magnetization of the sample. Our experiment yields a degree of polarization $P=(5.27\mathrm{}\pm 0.70) \%$. $P$ did not vary significantly over the energy range from 2.8 to 5.0 eV of the incident light.

An unexpected ordered state among Pr nuclei in the Van Vleck paramagnet PrBi is inferred from a sharp increase in specific heat at 10 mK as well as from the onset of strong irreversible heating when sweeping the field at these temperatures. Several possible explanations are discussed, among which the coupling between the nuclei via hyperfine interaction (within the ions) and exchange interaction (between the ions) is likely to be the true ordering mechanism.

We present the results of analysis of our measurements of the magnetic properties of the insulating ferromagnet Cr${\mathrm{Br}}_3$ near its critical temperature. From this analysis we obtain a mathematical representation of an equation of state valid over the entire critical region.

A parametric representation of the usual thermodynamic variables in the neighborhood of a critical point is proposed in terms of new variables $r$ and $\theta$. The representation is chosen so that the "scaling-law" behavior is entirely contained in the $r$ dependence, the $\theta$ dependence being free of critical singularities. Preliminary calculations show that the $\theta$ dependence may be chosen to have a rather simple form both in a ferromagnet and in fluids.

A generalized ring-locus model, previously introduced to explain the behavior of the deexcitation $\gamma$ pattern in inelastic $\alpha$-particle scattering, is applied to polarization effects in ($d,p$) reactions. The vector-polarization analyzing power of this reaction is shown to be almost independent of the angular width of the ring locus, but strongly dependent on the displacement of the ring locus relative to a plane through the center of the target nucleus.

By employing the reactions ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}(p,{}_{}{}^6{}_{}{}^{}\mathrm{He}){}_{}{}^{19}{}_{}{}^{}\mathrm{Na}$ and ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}(p,{}_{}{}^6{}_{}{}^{}\mathrm{He}){}_{}{}^{23}{}_{}{}^{}\mathrm{Al}$ [$\frac{d\sigma }{d\Omega }\sim 100$ nb/sr], the mass excesses of ${}_{}{}^{19}{}_{}{}^{}\mathrm{Na}$ and ${}_{}{}^{23}{}_{}{}^{}\mathrm{Al}$ are found to be 12.974 ± 0.070 and 6.766 ± 0.080 MeV, respectively [${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ = 0]. Since ${}_{}{}^{19}{}_{}{}^{}\mathrm{Na}$ is determined to be proton unstable, ${}_{}{}^{23}{}_{}{}^{}\mathrm{Al}$ should be the lightest, nucleon-stable member of the $A=4n+3\mathrm{}$, $T_Z=-\frac{3}{2}$ mass series.

We have observed 46 examples of the decay ${\Sigma }^{-}\to \Lambda e^{-}\nu$ and six of the decay ${\Sigma }^{+}\to \Lambda e^{+}\nu$. The branching ratios are, respectively, (0.52±0.09)×${10}^{-4\mathrm{}}$ and (0.16±0.07)×${10}^{-4\mathrm{}}$. A study of the internal variables distribution yields $\frac{G_V}{G_A}=-0.7\mathrm{}\pm 0.4$ for the combined sample of ${\Sigma }^{\pm }\to \Lambda e^{\pm }\nu$.

We present preliminary data which demonstrate that the ${\pi }^{-}p$ charge-exchange differential cross section at 180° in the momentum region between 1.8 and 5.0 BeV/c is quite similar in shape to the elastic ${\pi }^{\pm }$ differential cross sections at 180°.

We show that the $t$-channel Pomeranchukon with slope ${\alpha }^{\prime }={0.7}_{-0.10\mathrm{}}^{+0.16\mathrm{}}$ plus $s$-channel resonances provide a good model for the description of near forward pion-nucleon elastic scattering in the range 1.00 to 20 BeV/c.

The SU(3) singlet-octet mixing angle between $\eta$ and $x^0$ is expressed in terms of the masses of the members of the pseudoscalar meson nonet and a scalar strange meson $\kappa$. Using the recent experimental value $m_{\kappa }=1100\mathrm{}$ MeV, one obtains $\theta =23\mathrm{}°$, or $\theta =14\mathrm{}°$, depending on whether the angle is defined for mesons being at rest or moving with infinite momentum.

The $2{}_{}{}^2{}_{}{}^{}S_{\frac{1}{2}}^{}{}_{}{}^{}-2{}_{}{}^2{}_{}{}^{}P_{\frac{3}{2}}^{}{}_{}{}^{}$ interval has been determined to be 9911.38(3) MHz in atomic hydrogen, by using the rf electric dipole transitions $\alpha a$ and $\alpha b$. Combining this result with the current experimental values of the $2{}_{}{}^2{}_{}{}^{}S_{\frac{1}{2}}^{}{}_{}{}^{}-2{}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}$ interval, we obtain $\Delta E_{\mathrm{H}}=10969.20\mathrm{}\left(6\right)\mathrm{}$ MHz. The corresponding value for ${\alpha }^{-1\mathrm{}}$ is 137.0350(4).

Measurement of the spin-up from rest of ordinary liquids in cylindrical containers shows that the delay times measured by Pellam in liquid helium-II are not classical and that the normal-fluid spin-up is suppressed.

Collisional diffusion in long-mean-free-path, geometrically nonsymmetric regimes is characterized by Bohm-like scaling laws. A variational principle is found for calculation of diffusion constants.

Data are presented on the resistivity of granular aluminum films near the superconducting transition temperature $T_c$ for both dc and 20-GHz excitation. Comparison with a recent theory of the effect of fluctuations on the frequency-dependent resistivity above $T_c$ shows much less excess conductivity than predicted. A possible explanation for the discrepancy may lie in the incorrectness of a currently suggested form for the time-dependent Ginsburg-Landau equation.

The long-range order parameter of the fcc ordered ${\mathrm{Fe}}_3$Al structure, as measured by x-ray scattering, varies as ${(T_c-T)}^{\beta }$, with $\beta =0.307\mathrm{}$, in the range between 1 and about 10 K below $T_c$ (823 K).

The x-ray scattering from ${\mathrm{Fe}}_3$Al corresponds closely to a pair correlation function, $\frac{\exp (-\kappa r)}{r^{1+\eta }}$, with $\eta =0.080\mathrm{}\pm 0.005$, for temperatures from $2\times {10}^{-4\mathrm{}}{T}_c$ to $2.5\times {10}^{-2\mathrm{}}{T}_c$ above the critical ordering temperature $T_c$. The inverse length, $\kappa$, is proportional to ${(T-T_c)}^{\nu }$, with $\nu =0.649\mathrm{}\pm 0.005$.

By means of an electric field the triplet structure of the $A$ band in KBr:T1 is shown. A quadratic Stark effect is also observed.