We show that the strong laser field used in stimulated Brillouin scattering (SBS) will tend to decrease the Stokes shift of the Brillouin line in gases.

We advance a possible explanation of the recent experiments by Kaminsky on the polarization of deuterons passed through a magnetized Ni single crystal. The large polarization is attributed to a strong preference for ionization of the deuterium atoms which have an electron spin opposite to the direction of the magnetic field.

We use the equation-of-motion technique to establish a chain of equations for retarded, double-time Green's functions of an ideal gas. Exact termination of this chain allows reproduction of the usual results obtained by other methods.

We observe that the Landau theory of liquid ${\mathrm{He}}^3$ makes a definite prediction about the behavior of the liquid structure factor $S\left(k\right)\mathrm{}$ when $\hslash k\ll P_{\mathrm{F}}$. Using the two-parameter Ansatz $F\left(\chi \right)=F_0+F_1{P}_1\left(cos\chi \right)$ for the spin-symmetric part of the quasiparticle interaction function with $F_0$ and $F_1$ determined by zero sound and compressibility, we obtain a qualitatively good fit to recent x-ray data for $S\left(k\right)\mathrm{}$.

It has recently been shown experimentally that the thickness of a saturated helium film is independent of its state of superflow. We present a simple model in which the thickness of such a film is fixed by dynamical considerations at the gas-film interface, and the required balance of forces is then provided by relatively minor adjustments in the film surface tension.

We have observed that liquid crystals of the $p$-azoxyanisole type exhibit macroscopic rotational motion above a threshold voltage. The vortex motion of the birefringent liquid results in a lattice of cylindrical lenses whose focal lengths are voltage variable. These experiments are in excellent agreement with the dynamic predictions of the continuum theory.

It is shown that the zeros of the partition function of the anisotropic Heisenberg ferromagnet locate on the unit circle in the complex "fugacity" plane, and all the spin correlation functions are non-negative when no external magnetic field is present.

We prove that the free energy of an arbitrary monomer-dimer system is analytic in the density and temperature for nonzero density, and hence that the system has no phase transition. This result can also be used to locate the $z=e^{2\beta h}$ roots of the Heisenberg ferromagnet or antiferromagnet at high temperature.

We investigate the scattering of slow neutrons by the diamagnetic currents induced in an atom by an external magnetic field. The angular dependence of the diamagnetic scattering amplitude is given by $q^{-1\mathrm{}}\left[\frac{\mathrm{df}\left(q\right)\mathrm{}}{\mathrm{dq}}\right]$ where $q$ is the magnitude of the scattering vector and $f\left(q\right)\mathrm{}$ the charge form factor of the atom.

Scattering of electrons from surfaces of ZnO single crystals has been studied in ultrahigh vacuum with a high-resolution electron-impact spectrometer ($\Delta E<\mathrm{}20\mathrm{}$ meV, impact energy $E_0=1-100\mathrm{}$ eV). The energy-loss spectrum in specular reflection shows a series of equally spaced loss peaks. The characteristic loss energies [68.8 meV for the ($1\overline{1}00$) surface and 67.3 meV for the (0001) and the ($000\overline{1}$) surfaces] agree with the energies of optical surface phonons determined by the condition $\mathrm{Re}{\epsilon }_n\left(\omega \right)=-1\mathrm{}$.

Electron surface states on $d$-band metals are investigated by the method of matching the crystal wave function at the surface to the solution outside. On a (100) surface of an fcc metal such a state is found at an energy corresponding to 4-5 eV below the Fermi level $E_{\mathrm{F}}$ in Ni and 5-6 eV below $E_{\mathrm{F}}$ in Cu. This state explains peaks in the density of states seen in photoemission from Ni and Cu.

Optical absorption of GaN thin films shows previously unreported structure at 3.8 eV, which is interpreted as the excitonic "knee" due to transitions across the fundamental direct energy gap previously thought to occur at an energy of about 3.4 eV. We also give the first report of the specular reflectance of GaN; peaks were observed at 6.8, 9.5, and 10.7 eV.

We discuss the response of a crystal in the presence of a neutron distortion in the first-order self-consistent approximation and we stress the importance of the self-consistency condition. The resultant integral equation for the phonon energies is solved by direct matrix inversion instead of truncating a series expansion. Numerical results are presented for solid Ne and fcc ${\mathrm{He}}^4$ at 10.0 and 11.5 ${\mathrm{cm}}^3$/mole.

We report a novel time-of-flight measurement of the velocity of electrons responsible for the Gantmakher-Kaner oscillations as observed in transmission at microwave frequencies in single crystals of copper. These measurements imply a new effect giving rise to the anomalous field penetration.

The results of a calculation of the magnon energy for hcp cobalt are discussed with emphasis placed on the relationship between interatomic exchange and exchange stiffness in the $3d$ transition metals.

It is shown theoretically that the linear contribution to the specific heat enhanced by spin fluctuations in nearly antiferromagnetic metals exhibits no logarithmic increase as the critical boundary is approached, nor does a term like $T^3\ln T$ in the specific heat exist, in contrast to the case of nearly ferromagnetic metals.

The reaction ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}({}_{}{}^{12}{}_{}{}^{}\mathrm{C}, \alpha ){}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ has been observed to populate states at $E_x=16.30, 16.55, \mathrm{and} 16.84$ MeV with center-of-mass cross sections (at ${\ominus }_{\mathrm{c}.\mathrm{m}.\mathrm{}}=11\mathrm{}°$) of 1.8, 4.5, and 4.1 mb/sr, respectively. The evidence suggests that these states possess high angular momentum. Another state observed at $E_x=15.15\mathrm{}$ MeV could be the $J^{\Pi }=9^{+}$ member of the $K=2\mathrm{}$ rotational band.

$E1\mathrm{}$ transition rates from the septuplet of ${\mathrm{Bi}}^{209}$ are analyzed using a simple model in which a direct coupling between the octupole and the dipole states of the core nucleus ${\mathrm{Pb}}^{208}$ is taken into account. It is shown that by using reasonable parameters one can get results which are consistent with the observed decay rates.

Flux limits for monopoles in the primary cosmic radiation have been derived on the basis of muon-poor air-shower data and the analog of inverse Compton scattering of monopoles from universal microwave background photons. Calculations on both galactic and universal scales were performed. The resulting limits are generally smaller than existing experimental limits and are applicable to strongly interacting monopoles.

In a sample of 8300 events of the type ${\pi }^{-}p\to {\pi }^{-}{\pi }^{+}n$ and 6800 events of the type ${\pi }^{-}p\to {\pi }^{-}{\pi }^{0}p$ obtained with 2.3-BeV/c incident ${\pi }^{-}$, substantial backward ${\rho }^0$ production is seen. The decay angular distribution of these backward ${\rho }^0$ events was found to be anisotropic. The $u$ distribution for the backward ${\rho }^0\text{'}\mathrm{s}$ is compared with the theoretical predictions of the strong-cut Reggeized absorption model. A small amount of backward ${\rho }^{-}$ production is also seen.