The electronic energy spectrum of amorphous Ge is computed. Energy distributions of photoemitted electrons are determined, and the results are in excellent accord with experiment. Our analysis shows that the short-range order is primarily responsible for the observed spectral structure. Long-range disorder, however, has a strongly perturbing influence on some of the spectra. It appears that there is little difference between the valence-band density of states in the amorphous and crystalline forms, but increased disordering can cause a red shift of the ${\epsilon }_2\left(\omega \right)$ peak.

High magnetic fields applied at low temperature induce new nonlinearities in the electronic transport properties of the alkali halides. These nonlinearities are interpreted in terms of the onset of the extreme quantum limit and are important in the interpretation of cross-modulation cyclotron-resonance measurements in the alkali halides.

We find that whenever the bottom of the conduction band of an insulator lies at positive energy, the image potential gives rise to bands of surface states. We present lower limits for binding energies of electrons to the surface of liquid and solid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, Ne, ${\mathrm{H}}_2$, and ${\mathrm{D}}_2$. Interaction between electrons and surface phonons (solids) or ripplons (liquids) increases the binding. We argue that these states may have in fact been observed in liquid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$.

A weaker form of Griffiths' theorem is established for the ferromagnetic Heisenberg model.

We describe the observation of an effect which indicates unequivocally the absorption of latent heat at the spin-flip transition of Cr on warming and its evolution on cooling.

We have measured the magnetic susceptibility and heat capacity of DyP${\mathrm{O}}_4$ at low temperatures and compared our results with the exact series expansions based on the three-dimensional Ising model for the diamond lattice. There is excellent agreement between experiment and theory.

Using a Compton-suppression spectrometer with a central Ge(Li) detector, we have observed a 346.95-ke V gamma-ray transition between the $4_1^{+}$ and $2_2^{+}$ states in ${}_{}{}^{60}{}_{}{}^{}\mathrm{Ni}$. According to the simple vibration model, this so-called zero-phonon transition is strictly forbidden. A lower limit of 0.174 is placed on the ratio of the observed to the single-particle rates.

Differential cross sections and asymmetries were measured for the ($p, d$) reactions on ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$ at 17.3 MeV, ${}_{}{}^{61}{}_{}{}^{}\mathrm{Ni}$ at 16.6 MeV, and ${}_{}{}^{91}{}_{}{}^{}\mathrm{Zr}$ at 24.5 MeV, from 15° to 150°. With optical parameters fitting experimental cross sections and polarizations for both ingoing protons and outgoing deuterons, the distored-wave Born approximation gives a good account of the measurements.

A straightforward, purely single-particle analysis of the Coulomb energy shift in ${\mathrm{Sc}}^{41}$, ${\mathrm{Ca}}^{41}$ leads to an abnormally small radius for the $f_{\frac{7}{2}}$ valence neutron. Presented in this note is a correlational correction that may help to increase this radius. The calculation of this correction is stated in as general a fashion as is possible, and an estimate is made which leans heavily on a parametrization of the proton and neutron densities.

The smallness of nucleon photoabsorption would imply total photonucleus cross sections which vary as the number of nucleons in the nucleus, but if $\rho$ dominance is correct the resulting strong interactions would take place primarily with the surface nucleons. At Stanford Linear Accelerator Center we have measured the photoabsorption in H, D, C, Cu, and Pb and have found cross sections which vary as $\sim A^{0.9}$ indicating that the photon interacts, at least partially, as a strongly interacting particle.

An extension of the chiral ${\left[\mathrm{SU}\mathrm{}\right(3)\mathrm{}\otimes \mathrm{SU}\mathrm{}(3\left)\right]}_{\gamma 5}$ equal-time commutation relations to the light cone is proposed based on a universality defined by the ${\left[\mathrm{SU}\mathrm{}\right(3)\mathrm{}\otimes \mathrm{SU}\mathrm{}(3\left)\right]}_{\beta }$ algebra. Consequences concerning asymptotic lepton-hadron inelastic scattering are derived and found to be in good agreement with experiment.

Duality reproduces most current-algebra results and leads to octet enhancement for $S$-wave nonleptonic decays of baryons. Reasons for its inapplicability to $P$-wave decays are given.

The lifetime of the charged pion has been determined in flight. The agreement of our result, 26.02 ± 0.04 nsec, with experiments of comparable precision made with pions at rest provides the most precise verification of time dilation. In the model of Lundberg and Rédei this comparison sets an upper limit on a fundamental length of 3 × ${10}^{-15\mathrm{}}$ cm. Using the measurements of velocity and momentum for both ${\pi }^{+}$ and ${\pi }^{-}$, we also obtain $\frac{m\left({\pi }^{+}\right)}{m\left({\pi }^{-}\right)}=1.0002\mathrm{}\pm 0.0005$.

We have measured the angular dependence of the intensity of light scattered from xenon near its critical point, verified the Ornstein-Zernike theory, and determined the temperature dependence of the isothermal compressibility ${\kappa }_T$, the long-range correlation length $\xi$, and the direct correlation range $R$. The exponents describing the divergences of ${\kappa }_T$ and $\xi$ are, respectively, ${{\gamma }_{\mathrm{liquid}}}^{\prime }=1.228\mathrm{}\pm 0.028$, ${{\gamma }_{\mathrm{vapor}}}^{\prime }=1.244\mathrm{}\pm 0.017$, and ${{\nu }_{\mathrm{vapor}}}^{\prime }=0.57\mathrm{}\pm 0.05$. $R$ is essentially constant at ∼6 Å.

The saturation of linear or nonlinearly (explosively) unstable high-frequency, electrostatic flute modes in a mirror-confined plasma is discussed. The mechanism proposed is the perturbation of particle orbits by the wave electric fields.

Band-to-band optical pumping of spin-polarized conduction electrons is demonstrated in $p$-type GaSb at 4.2°K by measurement of the degree of polarization of the photoluminescence. Significant electronic polarization [42 (±8)%] is achieved, and experiments with a weak transverse magnetic field yield the electronic lifetime $\tau =6.0(\pm 0.7)\times {10}^{-9\mathrm{}}$ sec of the photocreated electrons.

We have determined by x-ray diffreaction that high-pressure gamma nitrogen is tetragonal with two molecules per unit cell in special position $f$ of space group $\frac{P{4}_2}{\mathrm{mnm}}$. At an average pressure and temperature of 4015±145 atm and 20.5±1.7 K, respectively, the unit cell dimensions are $a=3.957\mathrm{}$ Å and $c=5.109\mathrm{}$ Å, giving a molar volume of 24.09 ${\mathrm{cm}}^3$ which is in good agreement with the value 24.05 ${\mathrm{cm}}^3$ taken from piston-displacement measurements.

A new energy parameter ${\mathcal{E}}_d$ is introduced to describe dispersion of the electronic dielectric constant. This dispersion energy is found to obey an extraordinarily simple empirical relation in the more than 50 ionic and covalent crystals for which reliable refractive-index dispersion data are available. Based on this result we derive a structure-dependent electronic dielectric response function consisting of constant optical-frequency conductivity with high-and low-frequency cutoffs.

The reflectance of solid Ar has been measured at 20°K for an angle of incidence of 15° in the photon energy range from 10 to 30 eV using the synchrotron radiation of DESY. The reflectance data reveal a spin-orbit-split exciton series with sharp maxima converging to about 14 eV together with broader peaks above 14 e V due to transitions between the valence and conduction band. The results are compared with the absorption spectrum associated with the $2p$ core levels.

The dependence on beam energy and lattice geometry of the intensity of electrons diffracted from surfaces is evaluated using the inelastic-collision model. At energies below that of the second primary Bragg peak, qualitative features of the intensity profiles are related to the lattice geometry. The quantitative features depend sensitively on the scattering from the surface layer. The first detailed interpretation of such profiles is proposed for the (100) face of tungsten.