Energy distribution spectra of photoelectrons emitted normal to a (100) plane of tungsten show a pronounced peak located 0.4 eV below the Fermi level, which is attributed to surface states. It is very sensitive to gas adsorption and disappears as the surface is saturated with hydrogen in the ${\beta }_2$ state, corresponding to a coverage of 2.5×${10}^{14}$ molecules/${\mathrm{cm}}^2$.

We report the effects of large uniaxial stresses, which produce splittings and shifts large compared to the spin-orbit interaction, along the [001] and [111] direction on the wavelength-modulated reflectivity spectrum of Si in the region around 3.4 eV. Our results are interpreted in terms of both interband and intraband splittings of the orbital bands and indicate conclusively that the optical structure corresponding to the main peak in reflectivity around 3.4 eV is due to ${\Lambda }_3-{\Lambda }_1$ (or $L_{3^{\prime }}-L_1$) transitions.

We propose a mechanism for the mixing of acoustic magnons and optic phonons propagating along the $c$ axis in terbium observed at 79 K. The interaction involves an intermediate state in which an electron-hole pair is exicted virtually by the phonon and subsequently recombines into a magnon. This interaction becomes possible when the spin-orbit coupling is taken into account, and it also explains the mixing of optic magnons and acoustic phonons as seen in terbium at 200 K and dysprosium at 4.7 K.

Triple correlation measurements using the reaction ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}({}_{}{}^{12}{}_{}{}^{}\mathrm{C},{\alpha }_1){}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}_{}^{*}{}_{}{}^{}\to {\alpha }_2+{}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}\left(2^{+}\right)\to \gamma +{}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}(\mathrm{g}.\mathrm{s}.\mathrm{})$ have been made to determine spins and parities of several highly excited states in ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$. Our results allow unambiguous assignments of spin and parity $8^{+}$ to the states at 16.30 and 16.84 MeV. The group at 16.55 MeV is a doublet with one member having spin and parity $8^{+}$, while the other member is most likely a $9^{-}$ state.

Strong preferential excitation of the odd-parity levels in ${}_{}{}^{18}{}_{}{}^{}\mathrm{F}$ and sharply forward-peaked angular distributions have been observed in the reaction ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}({}_{}{}^6{}_{}{}^{}\mathrm{Li},t){}_{}{}^{18}{}_{}{}^{}\mathrm{F}$. These results imply that the reaction mechanism contains a direct component and that the odd-parity levels have large ${\mathrm{}\left(p\right)\mathrm{}}^{-1\mathrm{}}{\mathrm{}\left(\mathrm{sd}\right)\mathrm{}}^3$ configurations.

The reaction ${}_{}{}^{159}{}_{}{}^{}\mathrm{Tb}\mathrm{}(p,t)\mathrm{}{}_{}{}^{157}{}_{}{}^{}\mathrm{Tb}$ at 30 MeV strongly populates collective states in the residual nucleus. Angular distributions of $\beta$ and $\gamma$ vibrational and ground-state rotational band members are presented and compared with distorted-wave Born-approximation predictions. We also include evidence supporting the importance of indirect multiple-step processes accompanying the ($p,t$) reaction. The ($p,t$) reaction is shown to be a powerful spectroscopic tool for populating higher-lying rotational band members in odd-mass deformed nuclei.

The emission of ${}_{}{}^5{}_{}{}^{}\mathrm{He}$ ($T_{\frac{1}{2}}=8\mathrm{}\times {10}^{-22\mathrm{}}$ sec for decay into $\alpha +n$) in spontaneous fission of ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$ is established from a correlation measurement involving the direction and the kinetic energies of the neutrons and the long-range $\alpha$ particles. Approximately 11% of these $\alpha$'s are products of ${}_{}{}^5{}_{}{}^{}\mathrm{He}$ breakup. The initial energy of the fragments of the ${}_{}{}^5{}_{}{}^{}\mathrm{He}$ at scission are calculated from the properties of the ${}_{}{}^5{}_{}{}^{}\mathrm{He}$ decay. They are 31 ± 11 and 3.2 ± 0.9 MeV, respectively.

The (${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, $d$) reaction has been performed on ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ and ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}$ at 38 MeV. For ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ angular distributions were obtained and compared to distorted-wave Born-approximation calculations. One spectrum was taken for ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}$. A reduction in cross section is observed and is compared with the results of (${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$), ($p,t$), and (${}_{}{}^3{}_{}{}^{}\mathrm{He}$, $n$) experiments.

A direct operational approach to the solution of the Schrödinger equation has led to an iterative nonperturbative method for its solution. The method, when applied to the Mathieu equation and the anharmonic-oscillator equation, is superior to the perturbation-iteration method and to Rayleigh-Schrödinger perturbation theory both in terms of rate of convergence and range of coupling constant allowed.

We report a new type of counter based on the transition radiation from ultrarelativistic charged particles. The efficiency of the "transition counter" depends almost linearly on the Lorentz factor of the particle in the energy region covered and is over 80% for 2-GeV electrons. Particles heavier than electrons in a 2-GeV unseparated beam are effectively rejected. A possible application of the counter at multihundred-GeV accelerators is discussed.

It is suggested that elementary particles should be defined as irreducible unitary representations of the group of asymptotically flat space-times in general relativity. The implications of such a definition are described in physical terms. In particular, it is pointed out that this definition (unlike the corresponding "flat space-time" definition) explains the observed discreteness of elementary-particle spins. The possibility of using the definition to explain "internal" symmetries is discussed.

The bootstrap condition applied by Odorico to the scattering of pseudoscalar mesons is extended to processes involving vector mesons and photons. The $\omega -\varphi$ mixing angle is predicted to be the quark-model value. A photon interacting as a $U$-spin scalar is one of a small number of solutions.

The linewidths of $1s$ photoelectron energy spectra have been measured for carbon, nitrogen, and oxygen, each in a variety of molecules in the gas phase. The linewidths of a given element increase with decreasing binding energy of the $1s$ electron. We interpret these changes in linewidth to be due to changes in the lifetime of the $1s$ hole caused by changes in the chemical environment.

Widths of photoelectron lines associated with vacancies in core levels immediately below the valence shell are shown to depend on the chemical environment. The width variation is ascribed to change in vacancy lifetime. Valence electron density influences these lifetimes through its effect on Auger transition rates. Correlation of linewidth and chemical shift in electron binding energy is discussed.

We report the first successful measurements by cascade radio-frequency spectroscopy of the hyperfine structures of excited $S$ and $D$ states of rubidium. We obtain the following magnetic dipole coupling constants (in MHz): for ${\mathrm{Rb}}^{87}$, $A\left(7\mathrm{}{}_{}{}^2{}_{}{}^{}S_{\frac{1}{2}}^{}{}_{}{}^{}\right)=312.5\mathrm{}\pm 3.5$, $A\left(5\mathrm{}{}_{}{}^2{}_{}{}^{}D_{\frac{3}{2}}^{}{}_{}{}^{}\right)=14.1\mathrm{}\pm 0.5$, $A\left(5\mathrm{}{}_{}{}^2{}_{}{}^{}D_{\frac{5}{2}}^{}{}_{}{}^{}\right)=-8.0\mathrm{}\pm 1.5$; for ${\mathrm{Rb}}^{85}$, $A\left(7\mathrm{}{}_{}{}^2{}_{}{}^{}S_{\frac{1}{2}}^{}{}_{}{}^{}\right)=92.6\mathrm{}\pm 1.0$, $A\left(5\mathrm{}{}_{}{}^2{}_{}{}^{}D_{\frac{3}{2}}^{}{}_{}{}^{}\right)=4.1\mathrm{}\pm 0.5$. The anomalous, negative value of $A$ for the $5{}_{}{}^2{}_{}{}^{}D_{\frac{5}{2}}^{}{}_{}{}^{}$ state may be related to the anomalously small fine-structure interval of the $5D$ state of rubidium.

The predictions of the full two-regime neoclassical transport theory have been obtained by numerical computation; they are compared with observations on the ST Tokamak.

We analyze the effects of (i) the nonlinearity of the large-amplitude plasma wave, and (ii) the inhomogeneity of the plasma, on the excitation of the plasma wave by beating two laser beams.

The temporal correlations of thermodynamic concentration fluctuations have been measured in a chemically reactive system at equilibrium by observing fluctuations of the fluorescence of a reaction product. The experiment yields the chemical rate constants and diffusion coefficients and shows the coupling among them. Data are reported for binding of ethidium bromide to DNA.

Measurements of the spin diffusion coefficient $D$ and the NMR linewidth ${T_2}^{-1\mathrm{}}$ are reported for a ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ impurity in solid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ at molar volume 21 ${\mathrm{cm}}^3$. For $x_3<3\mathrm{}\times {10}^{-2\mathrm{}}$, $D{x}_3=(1.2\mathrm{}\pm 0.4)\times {10}^{-11\mathrm{}}$ ${\mathrm{cm}}^2$ ${\sec }^{-1\mathrm{}}$, where $x_3$ is the fractional impurity concentration, and for $x_3<2\mathrm{}\times {10}^{-3\mathrm{}}$, $T_2{x}_3=(1.1\mathrm{}\pm 0.3)\times {10}^{-4\mathrm{}}$ sec. These results conform with a model of "impuriton" excitations or "mass fluctuation waves" in which the quasiparticles move like a gas.

It is shown that when hyperfine interactions at ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$ nuclei are studied by both Mössbauer effect and time-differential perturbed angular correlations, information is obtained which is unavailable from either technique alone. In particular, previous ambiguities in the interpretation of ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$ Mössbauer spectra of Cu-Ni alloys are removed: The Mössbauer doublet is shown to be primarily due to a distribution of electric field gradients acting on the ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$ nuclei.