Auger electron peaks at 92 and 104 eV have been observed in the derivative $\frac{\mathrm{dN}\left(E\right)\mathrm{}}{\mathrm{dE}}$ of the secondary-electron energy distribution $N\left(E\right)\mathrm{}$ from clean polycrystalline beryllium. Existence of these two Auger transitions can be explained in terms of conduction-band electrons with $s$ character and $p$ character and is consistent with theoretical calculations. The observed Auger transitions can be expressed as $1s2s2s$ (92 eV) and $1s2p2p$ (104 eV).

The spectral photoelectric yield of RbCl has been determined in the photon energy range 10 to 40 eV by using synchrotron radiation as a continuous light source. Comparison of the absorption spectrum with the spectral yield measured with and without retarding potential reveals that the general features of the spectral yield are attributable to electron-electron scattering and the absorption spectrum. The yield exceeds unity in the region 21.0 to 25.0 eV, and the electron affinity is estimated to be 0.50 ± 0.05 eV.

Large 1LO Raman scattering near resonance in CdS is observed in the diagonal components of the Raman tensor $R^{\alpha \alpha }$ independent of crystal-symmetry selection rules. The data support the interpretation as an intrinsic bulk effect dependent on the finite wavelength of light.

We have observed electron standing-wave states in thin Pb films by electron tunneling. The simple theory includes the important fact that oriented crystalline films will vary in thickness only by discrete steps. As a result, certain "commensurate" energy levels play an important role in the experiment.

Recent field-emission tunneling experiments have shown a current-dependent tail in the energy distribution for energies above the Fermi energy. This tail can be understood in terms of the products of a cascade process initiated by the injection of hot holes (removal of electrons by field emission) into the interacting electron gas or metal conduction band. The derived shapes of the tails, numerical values of the high-energy distributions, and field dependences of the current in the tails are in good agreement with our experimentally observed results.

The static electric quadrupole moments of the ground and first excited states of nuclei in the $\mathrm{sd}$ shell are calculated from shell-model wave functions. The relative values of experimentally known moments of ground states are well reproduced by the calculations as are the relative values of the measured moments of $J^{\pi }=2^{+}$ first excited states. However, the absolute experimental values of the ground-state and exicted-state moments cannot be reproduced simultaneously with a single choice of effective charge.

A general technique is presented for finding upper and lower bounds on the value of any physical quantity consistent with measured values of other physical quantities and the assumption that all these quantities can be described by the same elementary excitation states. These bounds are independent of the details of the distribution of the states and in some instances can be quite restrictive.

The temperature dependence of the rotational displacement parameters below the second-order phase transitions in SrTi${\mathrm{O}}_3$ and LaAl${\mathrm{O}}_3$ at $T_a=105.5\mathrm{} \mathrm{and} 797$°K is described by an exponent $\beta =0.33\mathrm{}\pm 0.02$ down to $t=\frac{T}{T_a}=0.95\mathrm{}$. For smaller $t$'s there occurs a change to Landau behavior approximately followed between $t=0.9\mathrm{} \mathrm{and} 0.7$. The observation of static critical exponents near displacive phase transitions confirms now the notion of universality in this field.

Electronic charge densities are calculated as a function of position in the unit cell for several diamond and zinc-blende semiconductors using wave functions derived from pseudopotential band-structure calculations. The covalent bonding charge is also calculated for these crystals and is plotted against the ionicity scales of Phillips and Van Vechten and of Pauling. It is shown that an extrapolation to zero covalent bonding charge yields a critical value of the ionicity which separates four-fold coordinated and six-fold coordinated diatomic crystals. This value is in agreement with the empirical value obtained by Phillips and Van Vechten.

The demagnetization of the $4f$ state of metallic Ce as function of pressure was studied by magnetic susceptibility measurements. In contrast to the $\beta$ and $\gamma$ phases, the collapsed $\alpha$ phase does not show a local moment but exhibits instead a strong local exchange enhancement of the susceptibility. The susceptibility decreases linearly with increasing pressure in our measuring range and is estimated to decrease by 80% between the boundaries of the magnetic and the superconducting phases. The results are consistent with the Anderson model of local moment formation over the entire range of interest of the parameter $E_{4f}-E_{\mathrm{F}}$.

Coincidence experiments indicate that ($p,np$) reactions on ${\mathrm{Zr}}^{90}$ and ${\mathrm{Sn}}^{112}$ leave the residual nuclei in their ground states, whence neutron spectra can be deduced from measurements of proton spectra. Results are very different for the two nuclei. Analysis indicates that the variation of ${\sigma }_i$-the cross section for the inverse process-is larger than expected and in opposite directions for the two nuclei.

Analysis of radar-echo time delays, primarily between Earth and Mercury, yields an upper limit on the fractional variation of the gravitational constant of 4 parts in ${10}^{10}$ per year. Continuation of these radar measurements for five more years-even at the present level of accuracy-would allow the uncertainty to be reduced reliably to 3 parts in ${10}^{11}$ per year, a limit close to the effect predicted by some theorists.

One-dimensional numerical simulation of the development of the ion-acoustic instability in a plasma with mass ratio 1836 shows considerable electron heating but only small high-temperature tails or large-amplitude, undamped ion-acoustic waves in the ion distribution.

The asymmetry in the process $\gamma +p\to {\pi }^0+p$ with polarized photons has been measured at 6 GeV for momentum transfers from $t=-0.4\mathrm{} {\left(\frac{\mathrm{GeV}}{c}\right)}^2$ to $t=-1.1\mathrm{} {\left(\frac{\mathrm{GeV}}{c}\right)}^2$, using coherent bremsstrahlung from a diamond crystal. A coincidence was made between the recoil proton in a $1.6-\frac{\mathrm{GeV}}{c}$ spectrometer and one of the ${\pi }^0$ decay photons in a Lucite shower counter. The measured asymmetry $\frac{({\sigma }_{\perp }-{\sigma }_{\parallel })}{({\sigma }_{\perp }+{\sigma }_{\parallel })}$ is consistent with strongly dominant natural parity exchange in the $t$ channel.

Results for the ratios of the muon inelastic-scattering cross sections on carbon and copper to the cross sections on hydrogen, measured in the same experiment, are presented. The data are consistent with ratios of cross sections for real photoabsorption. In the kinematical region where coherent diffractive effects should be small or absent we find that the inelastic cross section varies as $A^{0.99\pm 0.01}$ and that $\frac{{\sigma }_n}{{\sigma }_p}=0.91\mathrm{}\pm 0.6$.

We have measured the cross section for backward inelastic production of ${\pi }^{\pm }$ by ${\pi }^{-}$ on protons at eleven beam momenta between 2.15 and 6.0 $\frac{\mathrm{GeV}}{c}$. We find that the laboratory cross sections $\frac{d^2\sigma }{{\mathrm{dp}}_{\parallel }}{{\mathrm{dp}}_{\perp }}^2$ at fixed transverse momentum $p_{\perp }$ and longitudinal momentum $p_{\parallel }$ have little or no dependence on beam momentum between 3.5 and 6.0 $\frac{\mathrm{GeV}}{c}$, and are sharply peaked toward zero ${p_{\perp }}^2$. The backward ${\pi }^{+}$ distributions in the laboratory from our experiment are nearly identical in shape to those obtained in the beam frame from $\mathrm{pp}$ experiments.

An operator representation for the behavior of the product of two electromagnetic currents near the light cone is used to discuss massive $\mu$-pair production in hadron-hadron interactions. Restrictions from the Stanford Linear Accelerator Center electroproduction experiments and from Regge theory are incorporated. Our predictions are in agreement with the recent Columbia—Brookhaven National Laboratory experiment.

We have observed the production of muon tridents in lead with an effective cross section of 51 ± 7 nb per nucleus, in agreement with the predictions of quantum electrodynamics. This measurement is sufficiently accurate that the interference term due to the presence of two identical muons in the final state is seen. The size of the measured interference term is 1.15 ± 0.25 times the value predicted for Fermi statistics.

It has been suggested that hadronic $s$- channel helicity is conserved in the diffractive region. If applicable to inelastic lepton-nucleon processes, such conservation has many implications which are illustrated for $\pi$ and $2\pi$ production. Polarization information is not needed for a first verification.

We have measured the rate of escape of electrons from the surface of liquid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ into the gas under the influence of an electric field. The rate of escape is orders of magnitude different, depending on whether the electrons were deposited on the surface from the liquid side or from the gas side.