A sharp increase of the rotatory power in the isotropic phase of cholesteric liquid crystals is observed near the isotropic-cholesteric liquid transition. This is interpreted as a manifestation of short-range chiral orientational order in the isotropic liquid. An application of the Landau-de Gennes theory predicts a ${(T-T^{*})}^{-\frac{1}{2}}$ temperature dependence, in agreement with measured data in the immediate pretransition region.

Photoelectron energy spectra have been measured on clean and cesiated samples of the fcc metals Rh, Ir, Pd, Pt, Cu, Ag, and Au. The behavior of structure on varying the photon energy shows a consistent pattern across the series in agreement with the resonance picture. The data are used to construct empirical band structures.

Simple and accurate expressions for the deformation potentials at symmetry points for shear strains are derived within the framework of the Green's function method. These formulas are applied to the strain-induced shifts of the energy levels of copper at $\Gamma$, $X$, and $L$ (including second-order effects when they are important), and the results are compared with the available data obtained from piezoreflectance measurements on single-crystal copper.

The diffusion of hydrogen in a single crystal of palladium (Pd${\mathrm{H}}_{0.03}$) has been studied by quasielastic neutron scattering. The results provide the best evidence yet obtained for the applicability of a simple jump model of hydrogen diffusion in a metal and confirm the predominant occupation of octahedral sites in the Pd crystal, with a mean residence time at 623 K of 2.8 psec between jumps.

With an improved on-line mass spectrometer we have discovered, by means of the reaction of 24-GeV protons on uranium, the very neutron-rich isotope ${}_{}{}^{32}{}_{}{}^{}\mathrm{Na}$ and measured its half-life. We have also produced in the same reaction the new isotopes ${}_{}{}^{33}{}_{}{}^{}\mathrm{Na}$, ${}_{}{}^{48-50}{}_{}{}^{}\mathrm{K}$, and ${}_{}{}^{227,228}{}_{}{}^{}\mathrm{Fr}$. There is evidence for shell effects in the cross sections of the new sodium isotopes.

The details of the structure previously observed in the high-energy proton-scattering continuum are inspected for collective multipole contributions. Evidence is shown that in the $E*\approx 10-25$-MeV excitation region of the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ continuum, at least dipole, quadrupole, and octupole excitations contribute to the structure of the cross section [$\sigma (\theta ,E*)$]. While the dipole and quadrupole strengths exhaust most of their corresponding sum rules, the octupole component does not. The possible nature of the less structured component at this continuum region is discussed.

Levels strongly populated in the reaction ${}_{}{}^{36}{}_{}{}^{}\mathrm{Ar}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$)${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ are compared with predictions for the lowest (oblate) 4p-4h rotational band in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$.

Data on the scattering of $\alpha$ particles from aligned ${}_{}{}^{165}{}_{}{}^{}\mathrm{Ho}$ was recorded over the energy range $14<~E_{\alpha }<~23$ MeV. Optical-model calculations are presented. It is shown that the data provide a clear resolution of the optical-model ambiguities found in previous analyses of $\alpha$ scattering from rare-earth nuclei.

A distorted-wave Born-approximation calculation of two-particle transfers between heavy ions is presented which does not treat the transferred nucleons as a cluster. Application is made to (${\mathrm{O}}^{18}$,${\mathrm{O}}^{16}$) reactions on the nuclei ${\mathrm{Mo}}^{92,94,96,98}$.

The rate of stopping muons at a depth of 1.45 × ${10}^5$ ${\mathrm{g}/\mathrm{c}\mathrm{m}}^2$ has been measured with a view to checking the anomalously high rate observed by Baschiera et al. at Mont Blanc. Muons produced locally could be separately identified with a large spark counter array. Their rate agrees with expectation based on muoproduction of hadronic cascades in the rock. The Mont Blanc result cannot be reconciled with ours if the excess stopping muons are produced by high energy muons.

Using a $2\pi -\mathrm{s}\mathrm{r}$ magnetic spectrometer, the branching ratio for $K^{+}\to e^{+}\nu$ relative to that for $K^{+}\to {\mu }^{+}\nu$ has been measured to be (2.42 ± 0.42) × ${10}^{-5\mathrm{}}$, in good agreement with the predictions of the $V-A$ theory.

We have measured the small-angle elastic scattering of ${\pi }^{+}$, ${\pi }^{-}$, $K^{+}$, $K^{-}$, $p$, and $\overline{p}$ incident on carbon at an incident momentum of 2.01 $\frac{\mathrm{GeV}}{c}$. Measurements of $K^{\pm }$ at 1.68 and 2.26 $\frac{\mathrm{GeV}}{c}$ were also recorded. The differential cross section $\frac{d\sigma }{d{q}^2}$ and the total nuclear cross section ${\sigma }_T$ are given. Data fitting provides values for the complex forward scattering amplitude $f\left(0\right)\mathrm{}$, and the slope parameter of the diffractive scattering distribution for each incident energy and particle.

The amplitude of ${K_S}^0$ regeneration in carbon is predicted by use of $f_{K^{+\left(0\right)\mathrm{}}}$ and $f_{K^{-\mathrm{}\left(0\right)\mathrm{}}}$ extracted from $K^{\pm }$ elastic scattering on carbon at momenta of 1.68, 2.01, and 2.26 $\frac{\mathrm{GeV}}{c}$.

A systematic numerical analysis of the single-particle distribution is presented in a dual-resonance model at energies presently accessible. The results are in reasonably good agreement with experiments. In addition, a criterion for the scaling limit in energy is suggested and the pion production rate is predicted to be much slower in the pionization limit than at intermediate energies.

Decay rates of the $2s_{\frac{1}{2}}$ metastable states of the hydrogen isoelectronic sequence are determined to lowest order in the fine-structure constant $\alpha$, and to all orders of $\alpha Z$, for elements with atomic numbers $Z$ ranging from 1 to 92. The $M1\mathrm{}$ decay rate is given in closed analytical form, whereas the $E1\mathrm{}$ rate is determined numerically. The two-photon $M1\mathrm{}$ decay rate is considered and found to be of negligible importance throughout the periodic table.

In Jaynes's semiclassical radiation theory, the decay of an excited atomic state depends on its initial population. For the radiative decay of the $2P$ level in atomic hydrogen, produced by pulsed excitation from the $2S$ level, the theory predicts a decay rate $\Gamma =(1-f)\mathrm{}{\Gamma }_0+\beta P$, where $\beta =f{\Gamma }_0$. Here $f$ is the initial $2S$ population, ${\Gamma }_0$ is the natural $2P$ decay rate, and $P$ is the $2P$ population relative to $f$. For $f=0.086\mathrm{}\pm 0.016$, and $P$ values in the range 0.15 to 0.64, we have measured $\beta =-(2.8\mathrm{}\pm 2.8)\times {10}^6$ ${\sec }^{-1\mathrm{}}$. The corresponding value from the semiclassical theory is $\beta =+(53.8\mathrm{}\pm 10.0)\times {10}^6$ ${\sec }^{-1\mathrm{}}$.

Linear polarization is shown to dominate circular polarization cross sections strongly for high-order multiphoton ionization of atoms.

We have measured the energies and widths of the x-ray lines from the $4f\to 3d$ transition in antiprotonic atoms of ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$. The results are discussed in terms of a phenomenological optical potential. We have also observed the x-ray line from the $3d\to 4p$ transition in the antiprotonic ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ atom.

This paper reports the experimental investigation of the multiphoton dissociation and ionization of the hydrogen molecule under the influence of Nd-glass laser radiation at 1.06 μm. The higher electronic states of the potential-energy curves of ${\mathrm{H}}_2$ are found to play the dominant role. An eleven-photon process is the initial step in the formation of ${\mathrm{H}}^{+}$ and a twelve-photon process is the initial step in the formation of $\mathrm{H}_2^{}{}_{}{}^{+}$.

A theory of the laser saturation spectroscopy experiments of Hänsch et al. is presented which is applicable at high values of the saturating laser beam. Phase- and velocity-changing collisions are taken into account.