By applying 75 kW of pulsed rf power to a decaying hydrogen plasma following turbulent heating, we have maintained a plasma density of ${10}^{12}$ to 5 × ${10}^{12}$ ${\mathrm{cm}}^{-3\mathrm{}}$ for the 600-μ sec duration of the rf pulse. Neutral energy analyzer measurements of ion temperature indicate $T_i\sim 100$ eV, while diamagnetic loop measurements indicate $100 \mathrm{eV}<T_e+T_i<200\mathrm{} \mathrm{eV}$. Probe measurements made using different equipment show discrete changes in the amplitude of the rf signals near the harmonics of the ion cyclotron frequency.

Molecular dynamics of a Widom-Rowlinson mixture of type-1 and -2 parallel hard squares appears to reveal a (first order) phase transition with plait point at density ${\rho }_1=0.74\mathrm{}$ of type-1 particles.

A one-fluid simulation model has been used to investigate diffusion in a low-$\beta$ toroidal plasma. The plasma behavior exhibits two disjoint regimes as a function of rotational transform. Larger transform yields unshocked flow and effectively classical plasma loss. With a decrease of only a few percent in transform angle, an abrupt transition occurs and a standing shock appears, with an associated large increase in plasma loss.

In an external magnetic field and near the transition temperature $T_{c2\mathrm{}}\mathrm{}\left(H\right)\mathrm{}$, bulk and thin-film superconductors exhibit an effective change to one- and zero-dimensional behavior in their fluctuation specific heats, which diverge like ${(\frac{T}{T_{c2\mathrm{}}}-1)}^{-\frac{3}{2}}$ and ${(\frac{T}{T_{c2\mathrm{}}}-1)}^{-2\mathrm{}}$, respectively. This enhancement effect is accompanied by a field-dependent broadening of the critical region.

The valence-band structures of MnO, CoO, NiO, ${\mathrm{Cu}}_2$O, CuO, and Re${\mathrm{O}}_3$ have been obtained by x-ray photoemission spectroscopy. It is found that in every case a narrow metal $d$ band lies above the center of the oxygen $2p$ valence band.

We have studied the magnetic field dependence of the decay time of the emission in KI: ${\mathrm{In}}^{+}$ and KI: ${\mathrm{Sn}}^{2+}$ produced at low temperatures by $A$-band excitation. The decay time decreases by almost 2 orders of magnitude in a field of 46 kG. This unusually large decrease has been correlated with the mixing due to the magnetic field among the excited states $\left|{\hat{A}}_{1\mathrm{u}}\right({{\Gamma }_1}^{-})〉$, $\left|{\hat{A}}_{2\mathrm{u}}\right({{\Gamma }_4}^{-})〉$, and $\left|{\hat{E}}_{\mathrm{u}}\right({{\Gamma }_4}^{-})〉$, which are distorted tetragonally by the Jahn-Teller effect.

Some experimental results concerning low-temperature emission intensity, decay times, and activator concentration dependence of the 4750-Å KCl: Tl emission are reported in order to clarify its origin. According to the experimental features, this emission is attributed to the de-excitation of the ${}_{}{}^3{}_{}{}^{}A_{1\mathrm{u}}^{}{}_{}{}^{}$ state, directly excited by the transition ${}_{}{}^1{}_{}{}^{}A_{1\mathrm{g}}^{}{}_{}{}^{}\to {}_{}{}^3{}_{}{}^{}A_{1\mathrm{u}}^{}{}_{}{}^{}$, as an alternative to the several discordant interpretations already given.

Temperature-modulated photoemission energy distribution curves, as well as modulated yields, have been obtained for gold at photon energies between 6 and 11 eV. Structure in the modulated spectra can be identified with the motion of particular one-electron energy bands upon heating, and agrees with the predictions of one-electron band theory as well as interpretations of temperature-modulated reflectance data.

A theory of the ultraviolet photoemission spectroscopy of metals with adsorbate covered surfaces yields $\Delta j\left(\omega \right)\propto {G_{\mathrm{aa}}}^I(\omega -{\omega }_0)-D{G_{\mathrm{aa}}}^R(\omega -{\omega }_0)$. $\Delta j\left(\omega \right)$ is the excess current at the energy $\omega$ produced by the adsorbates, ${\omega }_0$ is the photon energy, $\left(\frac{1}{\pi }\right){G_{\mathrm{aa}}}^I$ is the density of states at the adsorbate, and ${G_{\mathrm{aa}}}^R$ is the real part of the Green's function at the adsorbate. $D$ is nonzero if $\omega -{\omega }_0$ is degenerate with the metal energy bands, and can be large ($D\sim 1$) for typical experimental conditions.

The interactions of bound holes with TO and LO phonons in InSb have been observed in magneto-optical experiments. Theoretical estimates of the hole-phonon coupling strengths have been obtained.

An exact solution is given for the vibronic problem posed by nondegenerate $s$ and $p$ electronic states interacting in cubic symmetry via a triply degenerate $T_{1\mathrm{u}}$ vibrational mode. In the strong-coupling limit the vibronic ground state is found to be $s$-like, irrespective of the order of the $s$ and $p$ electronic states in the unrelaxed configuration. Applications to the interpretation of Stark effects and other experiments on $F$ centers in alkali halides are discussed.

We treat theoretically the simultaneous two-photon absorption and sum-frequency generation associated with exciton polaritons in noncentrosymmetric crystals. Expressions are derived for the two-photon absorption coefficient and for the intensity of the polariton beam. We describe the symmetry properties of two-photon absorption by longitudinal excitons and by transverse polaritons.

The angular dependence of the width of the exchange-narrowed Lorentzian EPR line in single-crystal TMPD-chloranil is shown to follow the second moment of the secular part of the electron dipolar interaction. This angular dependence is expected for spatially uncorrelated spin excitations.

The quadrupole interaction of the 247-keV state of ${}_{}{}^{111}{}_{}{}^{}\mathrm{Cd}$ recoil implanted into polycrystalline Cd metal has been measured by the time-differential perturbed angular-correlation technique, following Coulomb excitation. The resulting interaction frequencies at three temperatures are in agreement with the recently measured lattice quadrupole interaction in Cd. This observation of a usable electric field gradient for recoil nuclei suggests the possibility of measuring excited-state quadrupole moments by such time-differential studies following nuclear-reaction implantation into metals.

Optical-model analysis of x-ray transitions in $K$-mesic atoms gives an "effective" $\overline{K}-N$ scattering length $\overline{a}=\left[\right(0.44\mathrm{}\pm 0.04)+(0.83\pm 0.07\left)i\right]$ F. The large change in $\mathrm{Re}\overline{a}$ from the free value is explained by assuming additivity of the $\overline{K}N$ potentials.

Proton-proton bremsstrahlung cross sections have been measured at 156 MeV for the proton angles ${\theta }_1=15\mathrm{}°$ and ${\theta }_2=18\mathrm{}°, 21°, 24°, \mathrm{and} 27°$. The $\gamma$ rays were detected with a Cherenkov counter.

The binary fission cross sections measured with mica track detectors are threefold larger than with protons of 29 GeV. Ternary events are ∼ 1% of binary. With U, Bi, and Au there is little preference for emission of fragments into the forward hemisphere. There is no indication of interactions which involve large momentum transfers to heavy target nuclei from 29-GeV ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ ions. However, with Ag targets there is evidence of significant momentum transfer.

The reaction ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$(${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$)${}_{}{}^{26}{}_{}{}^{}\mathrm{Na}$ at $E\left({}_{}{}^7{}_{}{}^{}\mathrm{Li}\right)=36\mathrm{}$ MeV has been used to measure the mass excess of ${}_{}{}^{26}{}_{}{}^{}\mathrm{Na}$; a value of - 6.853±0.030 MeV was obtained. This result differs by 0.3-0.8 MeV from those previously determined from $\beta$-decay end-point measurements.

The excitation function for the process ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$′)${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$* (1.45 MeV) has been measured at 60°, 75°, and 90° lab over the energy range 34-58 MeV. At low energy the cross section rises as expected from Coulomb excitation of an electric quadrupole with a $B\left(E2\mathrm{}\right)\mathrm{}$ value of $(0.066\mathrm{}\pm 0.004)e^2$ ${\mathrm{b}}^2$. As the energy is increased further, the $2^{+}$ excitation function exhibits a deep valley, due to an interference between Coulomb and nuclear excitations, which is localized over a distance of ∼1 F and appears to be correlated with a rise in elastic scattering (relative to Rutherford scattering).

Elastic $\alpha$-nucleus differential cross-section data (15°-175°) are analyzed using a potential model. The real potential is calculated using an effective potential obtained from a global analysis of nucleon-$\alpha$ data. The resulting four-parameter model given an excellent representation of the $\alpha$-nucleus data. This representation is significantly better than can be obtained with a six-parameter optical model and is sensitive to the nuclear-nucleon density distribution.